The Wii is set to get a Soul Eater game title, ソウルイーター モノトーン プリンセス / Soul Eater Monotone Princess, set for release September 25th. The title is set to be a hybrid action/adventure game, centred on an original story, and the gameplay and adventure segments will be supplemented by anime cinematics produced by Bones. Of course, the game will have the same voice cast as the anime.
The spiel being given is that this is more on the side of mixed media than mere spin off, so it may be something to look out for. More details on the official site, though few screens at present. Via AnimeAnime.