There's also the game
Lips which is like Singstar (karaoke game) for the XBOX 360. Possibly, there are various versions of the game. I never tried it, but I guess it's okay. I expect the gameplay is roughly like the Singstar games, so the real difference between them I assume is the track list.
And it looks so cool and trendy too.
edit :
Sorry for mentioning a 360 game though .. Just .. thought I'd throw it out there. I see it's not ported for Wii.