Via http://serebii.net/index2.shtml
Keep in mind that there have been cases when a Pokemon game to be announced in CoroCoro was revealed somewhere else first, so this might be the same game as whatever is announced at Jump Festa (assuming TPC announces a game there at all).
Let the speculation continue!
In The Games Department
New Game Reveal Next Month
The new CoroCoro issue, released this week, has announced that a brand new Pokémon game is to be revealed. However, unlike people expect, this reveal isn't coming at Jump Festa but is in fact coming in the issue of CoroCoro next month, due out on January 14th 2012 in what they call a world first shocking announcement. It's currently unknown what game will be revealed, whether it will be main series or not but we'll provide information a few days before CoroCoro's release. Be sure to watch the site in case it comes early
Keep in mind that there have been cases when a Pokemon game to be announced in CoroCoro was revealed somewhere else first, so this might be the same game as whatever is announced at Jump Festa (assuming TPC announces a game there at all).
Let the speculation continue!