In the teaser for their upcoming preview of Epic Mickey, Game Informer stated that the game would be exclusive to the Wii. There's some doubt as to whether that's true, though.

On Monday, GI's teaser site had stated that the game was a Wii exclusive. However, sometime between then and today, any reference to the Wii was removed.

It's possible GI had been planning to keep the exclusivity secret until the article ran, but this information had already traveled far and wide before GI edited their site so there's no point to trying to correct the mistake. Another possibility is that the game isn't really a Wii exclusive. Maybe it's currently in development for the Wii but other platforms haven't been ruled out yet?