UAE is a famous Amiga emulator ported to the Wii. UAE Wii can be found on googlecode at uae-wii.googlecode.com, and is based on the source code of E-UAE. It allows you to play Stunt car racer, Turrican, Midwinter and the other good old Amiga games on your Wii. The port uses SDL Wii.
You can read about the current status on my blog. Interested developers should mail me at simon.kagstrom@gmail.com and I'll give you commit access to the googlecode repository.