Emulators: (OMG Zsnes!)
By far, the best emulator is ZSNES. Zsnes is also the fastest emulator of the SNES console. This wonderful emulator is made by zsKnight and _Demo_. This emulator has good sound and the ability to emulate super FX games such as Super Mario World II - Yoshi's Island. It is now able to emulate Starfox and Stunt Race FX with 3D objects (polygons). Zsnes has a very good GUI. I would recommend the windows port because is has compatibility with microsoft's directx software (DirectX 8.0 required to use windows port).
The Zsnes Homepage is at http://www.zsnes.com.
Zsnes hasn't been updated in awhile and nightly builds are no longer available. If you want a more up to date emulator, check out SNES9x.