Gamer's Internet Tunnel allows you to connect separate LAN's together and play online games with less packet loss in theory. As a practical upshot, you can play PS2 online games as well, like TimeSplitters 2. There's a how-to on setting up GIT with TS2 on NeoAvalon. It's a good overview of GIT as well, though you'll need to know a couple of things about networking. Similar projects include XBConnect (for Xbox) and Warp Pipe (for, you guessed it, GameCube). As usual, most of these are betas, but it's nice to see the development progressing quickly.