sega has said nothing to confirm either way.... unless it is a sonic FPS there is no reason to put it on the 360 since FPS games are the only ones to sell GREAT on the 360. Basically Nothing sells great on PS3... AC, and COD4 did because people wanted jaw dropping graphics. Sonic will not deliver there. It is casual. Either Wii exclusive or multiplatform are the only 2 logical choices for Sega.
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut