The Official Nintendo Magazine UK contacted SEGA which they replied “no comment”.
It says that “Sonic Anniversary” will be available for Nintendo DS, PSP, Play Station 3 and Wii, with a Xbox 360 version to be confirmed. Although as according to a comment on the Spanish social network Tuenti, is said that there was going to be 4 Sonic games: Sonic Anniversary, Sonic 3DS (title not given yet), Mario and Sonic 3 (It's possibly not a sports game) and Sonic 4 Episode 2. Even it might incorrect that information. Even though the Sonic 3DS game might be a Nintendo 3DS version of the game, although we don't know yet until SEGA puts it on its websites. It said that it will be a mix of 2D and 3D with stages from various Sonic titles. Even Sonic the Hedgehog 4 Episode 2 is in production at the moment.