2dfighter Freeplay emulator and matchmaking server.

[Nagato]

it's very easy to do, you sign up, they send you a password to ur E-mail, once you get the password, hit play at the top of the 2dfighter.com, put ur password in, and you are now able to play people from all around the globe in nearly any 2D fighting game made to date(besides guilty gear).

Site:
http://2dfighter.com/

when you have ur roms, go to settings, and configure where your roms are located, so if you have kawaks or mame or GGPO, just direct it to their roms folder.

if you want to host games, you must open port 27886.
you can challenge anybody, or anybody can challenge you.