For those who want to play game like TMNT (4P), X-Men (6P), Aero Fighters 2 (4P), or even 2P games that 2DF just doesn't support, they will need to use mameppk. It has a Kaillera option for it for online play. And another cool thing is that Kaillera supports 4 player mame games (while 2DF can only support 2 player). For a guide on how to set that up, click
here.
For those who want this emulator:
http://kaillera.com/files/mameppk_bin_gcc-0.119-20070914.zip
1. Unzip the emulator into a folder. Don't unzip the MAME game.
2. Put games in roms folder inside the mameppk folder BEFORE opening the program.
3. Once you have opened the program, press F5 and it will automatically search for mame games on your computer.
4. Before you go off to play online, highlight Available. You should see games with little green chips besides them. Keep this highlighted because it is important.
5. Go to file, then click on Kaillera
Netplay, not start server.
6. Enter you desired user name (GBAtemp user name so we can recognize you). Then click enter IP and paste: 69.114.136.202:27888 then press connect.
7. Now you can either make a room or join one. You can only join or make a room with the games that are on the highlighted Available list. If that list is not highlight, then it will say you do not have the ROM.
If you have anymore problems or question you can reach me on GBAtemp's IRC under the nick: Josh
GameDragons's server: 69.114.136.202:27888