Call Sony.
They can tell you the guy's IP if he tries to go online with it.
Then call that area's local ISP(s). Tell them the IP and time and they can get you the address.
You can then find out where your PS3 is. If it's his "house", or in the same area, you know he did it.
Pay someone kid in the area $50 to smash out their windows and grab it for you.
Then take the PS3 from the kid and beat him up.
If the cops come by, you've got your PS3 and never had anything to do with nothing.
The guy who stole the PS3 beat up the kid for smashing his windows.
The kid will have been beat so badly (if you do it right) that they'll think it was the other guy.