Fuzziqer has released the public beta of his popular Control Sim application for Gamecube. This application allows you to play several multiplayer GC games over the internet. The public beta comes with scripts to support the US versions of Super Smash Bros. Melee, Super Monkey Ball 2, and Sonic Adventure 2 Battle. Support for other games can be added by users. You can find more information about this application here.
http://www.gcdev.com/