Check out  Emulation Station!!!!

MAME32 - The best Emulator for old Arcade classics.
NES - The best Emulator for Nintendo games.
SNES - The best Emulator for Super Nintendo games.
Sega - The best Emulator for Sega Genesis games.

Currently working on Turbo Graphix16, Nintendo 64,
Playstation and even Xbox.

More to come soon!!!!