Here is a full list of all the known developers for each company
Sony
1st party
SCEJ - last notable games they made was Patapon 2 and Super Stardust Portable then they made some niche PSP games could be maing one of the NGP games like Smart As
SCEI - making Gravity Daze, Broken and Reality fighters for NGP
Team ICO - making Last Guardian
Eat Sleep Play - making Twisted Metal
Polyphony Digital - likely to be working on Gran Turismo 6
Naughty Dogg - making Uncharted 3
Santa Monica - making GoW4
San Diego - they recently MLB and helped make Sports Champion with Zindagi
Zipper - recently released SOCOM4
London - making Eyepet and Friends
Cambridge - making Killzone NGP
Guerilla Games - making new IP for PS3
Liverpool - likely to be making WipeOut NGP
Bend - making Uncharted NGP
Evolution - recently released MotorStorm 3
BigBig - making LittleDeviants for NGP
MediaMolecule - making NGP game, likely to be LittleBigPlanet
The Workshop - making Sorcery for Move
3rd Party
Zindagi Games - made Sports Champion, rumored to be making another Move game
Supermassive Games - made Tumble and Start the Party
Cohort Studios - helps make Buzz Jr and made The Shoot for Move
Seed Studios - making Under Siege for PS3
ColdWood Interactive - made The Fight for Move
Bluepoint Games - making Team ICO collection, rumored to be making another HD collection
Sucker Punch - making new IP and maybe Sly 4
Clap Hanz - making Everybody's Golf for NGP
Career Soft - usually work on Growlanser games
VooFoo Studios - making HustleKings NGP
Media Vision - last games they made where Wild Arms XF and Valkyria Chronicles 3 for PSP
Insomniac - making Ratchet All 4 One and Resistance 3, then they will go 3rd party multiplatform
ThatGameCompany - making Journey for PSN
Ready At Dawn - last games they released was Ghost of Sparta for PSP
HighImpact games - last game they released was Jak and Daxter the lost frontier for PSP/PS2
Lightbox Games - making Starhawk
United Front Games - the last game they co developed Modnation Racers with San Diego
Quantic Dreams - making 2 new IPs for PS3
Relentless Studios - usually make Buzz games
Novarama - made Invizimals for PSP, could potentially make another AR game for NGP
Q Games - usually make PixelJunk games
Nihilistic - making Resistance NGP
Tarsier Studios - making City of Metronome
Dontnod Entertainment - making new AAA action adventure game commissioned by SCE
Nintendo
1st party
EAD Comprehensive - making Star Fox 3DS
EAD 1 - recently made Nintendogs and now making Mario Kart 3DS
EAD 2 - making Wii Play Motion
EAD 3 - making Zelda Skyward Sword
EAD 4 - making Pikmin 3
EAD 5 - recently released Steel Driver
Tokyo - making Super Mario 3DS
NST - recently released Mario vs DK miniland mayhem
Monolith - recently released Xenoblade
NSD - last game released was Brain Age Express for DSiware
Retro - rumored to be making WiiHD game
Browny Brown - last game released was A Kappas Tail for DSiWare
Intelligent Studios - making Paper Mario 3DS
Project Sora - making Kid Icarus
Hal - making Kirby Wii and Kirby DS
3rd party
AlphaDream - last game was Mario and Luigi Inside Story
Creatures - usually make Pokemon Rangers games
Ganbarion - making Pandora's Tower
Camelot - recently released Golden Sun Dark Dawn
Genius Sonority - rumored to be making Pokemon XD port for 3DS
Good-feel - recently released Kirby Epic Yarn
Monster Games - recently made PilotWings Resort
Noise - make Custom Robo games
Skip Ltd - usually make Chibi Robo and Art Style games
Treasure - making radiant Silvergun for XBLA
GameFreak - making next Pokemon games
MS
1st party
343 Industries/Wingnut - rumored to be making Halo CEmake
BigPark - last game released was Joy Ride
Good Science Studio - last game was Kinect Adventures
Lionhead - last game was Fable 3
RARE - last game was Kinect Sports
Xbox Live Productions - last game was South Park Tower Defense
Turn 10 - making Forza 4
3rd Party
Crytek - making Codename Kingdoms
Epic - making Gears 3
Gas Powered Games - making Age of Empires Online
Remedy - last game released was Alan Wake
Ruffian - last game was Crackdown 2
Undead Labs - making XBLA game
NanaOn-Sha - making Haunt for Kinect
Terminal Reality - making Star Wars Kinect
Grounding Inc - making Project Draco for Kinect
Grasshopper Manufacture - making Codename D
List without the speculation
Sony
1st party
SCEJ - last notable games they made was Patapon 2 and Super Stardust Portable then they made some niche PSP games could be maing one of the NGP games like Smart As
SCEI - making Gravity Daze, Broken and Reality fighters for NGP
Team ICO - making Last Guardian
Eat Sleep Play - making Twisted Metal
Polyphony Digital - likely to be working on Gran Turismo 6
Naughty Dogg - making Uncharted 3
Santa Monica - making GoW4
San Diego - they recently MLB and helped make Sports Champion with Zindagi
Zipper - recently released SOCOM4
London - making Eyepet and Friends
Cambridge - making Killzone NGP
Guerilla Games - making new IP for PS3
Liverpool - likely to be making WipeOut NGP
Bend - making Uncharted NGP
Evolution - recently released MotorStorm 3
BigBig - making LittleDeviants for NGP
MediaMolecule - making NGP game, likely to be LittleBigPlanet
The Workshop - making Sorcery for Move
3rd Party
Zindagi Games - made Sports Champion, rumored to be making another Move game
Supermassive Games - made Tumble and Start the Party
Cohort Studios - helps make Buzz Jr and made The Shoot for Move
Seed Studios - making Under Siege for PS3
ColdWood Interactive - made The Fight for Move
Bluepoint Games - making Team ICO collection, rumored to be making another HD collection
Sucker Punch - making new IP and maybe Sly 4
Clap Hanz - making Everybody's Golf for NGP
Career Soft - usually work on Growlanser games
VooFoo Studios - making HustleKings NGP
Media Vision - last games they made where Wild Arms XF and Valkyria Chronicles 3 for PSP
Insomniac - making Ratchet All 4 One and Resistance 3, then they will go 3rd party multiplatform
ThatGameCompany - making Journey for PSN
Ready At Dawn - last games they released was Ghost of Sparta for PSP
HighImpact games - last game they released was Jak and Daxter the lost frontier for PSP/PS2
Lightbox Games - making Starhawk
United Front Games - the last game they co developed Modnation Racers with San Diego
Quantic Dreams - making 2 new IPs for PS3
Relentless Studios - usually make Buzz games
Novarama - made Invizimals for PSP, could potentially make another AR game for NGP
Q Games - usually make PixelJunk games
Nihilistic - making Resistance NGP
Tarsier Studios - making City of Metronome
Dontnod Entertainment - making new AAA action adventure game commissioned by SCE
Nintendo
1st party
EAD Comprehensive - making Star Fox 3DS
EAD 1 - recently made Nintendogs and now making Mario Kart 3DS
EAD 2 - making Wii Play Motion
EAD 3 - making Zelda Skyward Sword
EAD 4 - making Pikmin 3
EAD 5 - recently released Steel Driver
Tokyo - making Super Mario 3DS
NST - recently released Mario vs DK miniland mayhem
Monolith - recently released Xenoblade
NSD - last game released was Brain Age Express for DSiware
Retro - rumored to be making WiiHD game
Browny Brown - last game released was A Kappas Tail for DSiWare
Intelligent Studios - making Paper Mario 3DS
Project Sora - making Kid Icarus
Hal - making Kirby Wii and Kirby DS
3rd party
AlphaDream - last game was Mario and Luigi Inside Story
Creatures - usually make Pokemon Rangers games
Ganbarion - making Pandora's Tower
Camelot - recently released Golden Sun Dark Dawn
Genius Sonority - rumored to be making Pokemon XD port for 3DS
Good-feel - recently released Kirby Epic Yarn
Monster Games - recently made PilotWings Resort
Noise - make Custom Robo games
Skip Ltd - usually make Chibi Robo and Art Style games
Treasure - making radiant Silvergun for XBLA
GameFreak - making next Pokemon games
MS
1st party
343 Industries/Wingnut - rumored to be making Halo CEmake
BigPark - last game released was Joy Ride
Good Science Studio - last game was Kinect Adventures
Lionhead - last game was Fable 3
RARE - last game was Kinect Sports
Xbox Live Productions - last game was South Park Tower Defense
Turn 10 - making Forza 4
3rd Party
Crytek - making Codename Kingdoms
Epic - making Gears 3
Gas Powered Games - making Age of Empires Online
Remedy - last game released was Alan Wake
Ruffian - last game was Crackdown 2
Undead Labs - making XBLA game
NanaOn-Sha - making Haunt for Kinect
Terminal Reality - making Star Wars Kinect
Grounding Inc - making Project Draco for Kinect
Grasshopper Manufacture - making Codename D
List without the speculation
AniHawk said:bold/italic = in development
SONY
SCEJ - echochrome ii (2010), patapon 3 (2011)
Team ICO (part of scej) - shadow of the colossus (2005), the last guardian (2011)
Polyphony Digital - gran turismo psp (2009), gran turismo 5 (2010)
Naughty Dog - uncharted 2 (2009), uncharted 3 (2011)
Santa Monica - god of war ii (2007), god of war iii (2010)
San Diego - sports champions (2010), mlb 11: the show (2011)
Zipper - mag (2010), socom 4 (2011)
Bend - resistance retribution (2009), uncharted ngp (2011/2012)
London - singstar dance (2010), eyepet and friends (2011)
Cambridge - tv superstars (2010), killzone ngp
Guerilla Games - killzone 3 (2011), unannounced ps3 title
Liverpool - wipeout pulse (2007), wipeout hd (2008)
Evolution - motorstorm: pacific rift (2008), motorstorm: apocalypse (2011)
BigBig - motorstorm: arctic edge (2009), little deviants (2011/2012)
MediaMolecule - littlebigplanet (2008), littlebigplanet 2 (2011)
The Workshop - sorcery (2011)
not sure if the workshop is actually a first-party studio.
NINTENDO
EAD Comprehensive - super mario 64 ds (2004), star fox 64 3d
EAD 1 - nintendogs + cats (2011), mario kart 3d (2011)
EAD 2 - wii sports resort (2009), wii play motion (2011)
EAD 3 - the legend of zelda spirit tracks (2009), the legend of zelda skyward sword (2011)
EAD 4 - new super mario bros. wii (2009), pikmin 3 (2011/2012)
EAD 5 - wii fit (2007), wii fit plus (2009)
Tokyo - super mario galaxy 2 (2010), super mario 3d (2011/2012)
NST - aura-aura climber (2010), mario vs. donkey kong mini-land mayhem (2010)
Monolith - disaster: day of crisis (2007), xenoblade (2010)
SDD - jam with the band (2008), brain age express (2008)
SPD 1 - metroid: other m (2010), rhythm tengoku wii (2011)
NSD - personal trainer: walking (2008), cooking guide (2008)
nd cube - tube slider (2003), wii party (2010)
Retro - metroid prime trilogy (2009), donkey kong country returns (2008)
Brownie Brown - a kappa's trail (2009), fantasy life (2011)
Intelligent Systems - fire emblem 3r (2010), paper mario 3d (2012)
Project Sora - kid icarus uprising (2011)
MICROSOFT
343 Industries - halo series
BigPark - kinect joy ride (2010)
Good Science Studio - kinect adventures (2010)
Lionhead - fable ii (2008), fable iii (2010)
RARE - banjo-kazooie nuts & bolts (2008), kinect adventures (2010)
Xbox Live Productions - fable ii pub games (2008), south park let's go tower defense (2009)
Turn 10 - forza 3 (2009), forza 4 (2011)
MGS Mobile Gaming - ilomilo (2010), the harvest
AniHawk said:SONY THIRD PARTY PARTNERS
Cohort Studios - buzz! junior dino den (2009), the shoot (2010)
Bluepoint Games - god of war collection (2009), ico and shadow of the colossus collection (2011)
Sucker Punch - infamous 2 (2011), sly 4, new ip
Clap Hanz - hot shots tennis (2010), hot shots golf ngp (2011/2012)
VooFoo Studios - hustle kings (2010), hustle kings ngp (2011/2012)
Insomniac - ratchet all 4 one (2011), resistance 3 (2011)
ThatGameCompany - flower (2009), journey (2011)
HighImpact games - secret agent clank (2008), jak and daxter ii: the lost frontier (2009)
Relentless Studios - buzz! brain of... (2009), buzz! quiz world (2009)
Tarsier Studios - littlebigplanet 2 dlc (2011), the city of metronome
Dontnod Entertainment - unannounced title
Titan Studios - fat princess (2009), fat princess: fistful of cake (2010)
Lightbox Interactive
Eat, Sleep, Play - twisted metal: head-on extra twisted edition (2008), twisted metal (2011)
NINTENDO THIRD PARTY PARTNERS
Hal Labs - kirby ds (2011), kirby wii (2011)
AlphaDream - postpet ds (2008), mario & luigi: bowser's inside story (2009)
Ambrella - my pokemon ranch (2008), pokemon rumble (2009)
Creatures - pokepark wii (2009), pokemon ranger guardian signs (2010)
Good-feel - wario land shake it (2008), kirby's epic yarn (2010)
Noise - custom robo arena (2006), go go cosmo cops (2009)
Skip Ltd - captain rainbow (2008), artstyle games (2008-2010)
GameFreak - pokemon soulsilver/heartgold (2009), pokemon black/white (2010)
MICROSOFT THIRD PARTY PARTNERS
Epic - shadow complex (2009), gears of war 3 (2011)
Remedy - max payne 2 (2003), alan wake (2010)
Ruffian - crackdown (2007), crackdown 2 (2010)
Undead Labs - xbla title
Grounding Inc - project draco
Signal Studios - toy soldiers (2010), toy soldiers: cold war
just my take on the third party situation