Text taken fromGP32emu.com:
Ryleh sent Atrkid a beta of his WIP NES emulator fNES32 for the GP32. Its looking great so far running at around 100% speed with sound on Frame Skip 1 on Mario 1 for example, the sound isnt quite perfect in some games just yet but its definately playable. Most of the games he tested worked great, just some issues with some games such as Megaman 3 in the stage selection screen, Zelda when changing screens and GFX glitches in Kirby 3.Ryleh is planning to add multiplayer, snapshots and savestates later today and will probably fix some other bugs like the sound and game errors mentioned above.
Screenshots can be viewed over at GP32emu.