The Adapter Factor HD - Mayflash Wii Classic Controller Pro to USB Review - YouTube
Nintendo's Wii Remote As A MIDI Controller
The Raphnet Wii Classic Controller to USB is the real del. It's seriously as good as a Wired Xbox 360 guitar. Legitimately buy one of these if you have a Wii Guitar.
wusbmote: Wiimote accessory to USB adapter
Wii Classic Controller to PC USB Adapter
raphnet. - Wusbmote: Wiimote accessory to USB adapter
Best Buy: GameCube Controller Adapter for Select Nintendo Consoles Black HACAGGGKA