Mame

Multiple Arcade Machine Emulator

http://www.mame.net/

http://www.mame.dk/ (its dead,man)

http://www.mameworld.net/

http://www.cybertechdesign.net/mameroom/

IRC: EfNet:  #roms #mame (small) Cyberjunks: (irc.cyberjunks.net) #roms Newnet: #emuchina #tosec

Good Tutorials on Mame and more: http://www.mameworld.net/easyemu/