Set-up: GC

[Zebulan7]

How do I set my modem to share the internet? I use broadband

[Rich_T]

without trying to state the obvious
theres some information in the instruction booklet, as well as on nintendos website, help section;
http://www.nintendo.com/online/index.jsp

You can also get information on setting up via the x box live website, if you are using broadband, the set up is virtualy identicle to that of an X box, it also lists how to set up to a router, a direct conection o a broadband modem( with ethernet out) and internet conecton sharing.
just replace the X box with a gamecube

http://www.xbox.com/en-GB/live/start/connect/