At E3 2006, there was information on the new Sonic title for PS3 and Xbox 360, but Sega also announced it was making an entirely new title exclusively for the Wii - Sonic Wild Fire (working title). It is still unknown what, if any, significance "Wild Fire" means to the playability. However, a batch of new screens gives us a better indication of the graphics, speed and actual control method.
In some of the screens, in the bottom left a small icon is featured with a Wiimote. We can see hints to indicate tilting the Wiimote left and right, a means of steering as Sonic hurtles along the course. This would be the same control method as demonstrated in ExciteTruck. We can also see button presses mid-air, probably to jump, but there could be some other mysterious use. In any case, that's enough speculation for now - jump on over to check the screens out in the Media Panel.
Sonic Wild Fire is scheduled for a 2007 release.