According to the recent issue of Nintendo Power magazine (August), they have confirmed the following six titles as confirmed launch games for the Wii console:
The Legend of Zelda: Twilight Princess
Metroid Prime 3: Corruption
Dragon Quest Swords: The Masked Queen and the Tower of Mirrors
Super Monkey Ball: Banana Blitz
Rayman Raving Rabbits.
It has been widely reported that the codenamed Super Mario Galaxy was never going to be a launch title so no surprises there. Im sure many more titles will be added to the list as the release dates draw nearer.