iChat is a headache. Granted the video quality is decent, it's still a hassle. I don't even have a router, and I can't get it to work properly.
Basically when you log into iChat (AIM) click the little video camera thingy next to your buddies screen name. Your buddy needs to have a fairly updated version of AIM as well. When you click the icon, it should send in a request which he will then approve. This is a good time to make sure you are fully clothed
Also, the thing about iChat is that there is a very good chance the problem isn't on your end, but on his. If your friend has a router, he will need to configure it properly. In addition, depending on what kind of networks the both of you are on, you may have high bandwith and your friend may have low. This creates problems as well.
Also, if he's a Window's user, the problem gets only more difficult. Everyone rants and raves about iChat, but it's lack of compatability with Windows based machines irritates me.
I wish Adium had video support, life would be beautiful then.