
FCE Ultra GX is an NES emulator based on FCEUX. With it you can play NES games on your Wii/GameCube. The GUI is powered by libwiigui.
Features
Wiimote, Nunchuk, Classic, and Gamecube controller support
iNES, FDS, VS, UNIF, and NSF ROM support
1-4 Player support
Zapper support
RAM / State saving support
Custom controller configurations
SD, USB, DVD, SMB, Zip, and 7z support
Cheat support (.CHT files)
IPS/UPS/PPF automatic patching support
NES Compatibility Based on FCEUX 2.1.5

Full detail http://wiibrew.org/wiki/FCE_Ultra_GX