Amazon.com: ELECOM Wii USB Adapter, Game Classic Controller / Classic Controller Pro to USB, Adapter for Windows PC for only one Player, 1m / 39 inch Length (JC-W01UWH)
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.
raphnet. - Classic controller to USB adapter - V3
raphnet. - Dual Gamecube controller to USB adapter
raphnet. - Classic controller to Gamecube/Wii adapter
raphnet. - Classic controller to USB adapter - V3
raphnet. - Classic controller to USB adapter - V3
raphnet. - Classic controller to USB adapter - V3
raphnet. - Wusbmote: Wiimote accessory to USB adapter