You can download it here then next you're gonna need some ROMS to use it on. Google is your friend here...or ask...someone...
Stick your new gold in the roms directory then make sure the game will load up and play (remember to enable a joystick).
Once your up and running it's time to try network play.
Click File>Play network game and you're presented with this screen

Stick a username in the box. Then double click a server name in the box above the username field which should be agreed by everyone so we don't get confused.
The black boxes are a bug. They are supposed to be buttons (connect, refresh etc) but don't worry about it.
Then we enter the server room.

It features chat and displays what is going on on the server like who is playing and what game, emulator etc. I chose a shit screenshot of a server and now my photoshop is being retarded so you just have to believe me.
To join a game, just double click the one in the lower box (current games) or just start one pressing the correct button and selecting from a drop down menu of alphabeticly ordered ROM files that are available.
After that then, God knows. The game should start off as normal.
The last time I tried it I got chatting with a Yank and played classics like Golden Axe, Wrestlefest and Metal Slug until the stupid hours of the morning. Great laugh.
Any questions just ask or PM. This is more of an interest check than a "OMG CHECK THIS OUT GUYZ!!111".




