If you have the japanese version of the #Reload for PC, japanese people have patched it so you can play head to head online.
There is almost no lag from what I've felt, and I have SO much fun!
GGXXNET
Download the OLD 1.20 then get the 3 patch AFTERWARD.
Then patch your ggxx.exe (it'll back it up for you)
Then set your online options (Name, color scheme for you character, and stuff like that)
Make sure you have "Shortcuts" enabled in the ingame options, and you'll see two new options: "VS NET" and "REPLAY." Replay is all of your games that you've played played-back for you, and VS Net is the net option.
A few hints to get it working:
The Delay frames denotes WHICH cgi you should link to in your options. Usually delay set to 4 and the delay4 lounge has the most people, so I suggest that. Other then that not a lot of stuff REALLY makes a difference. Also, foward your ports :3