http://www.projectcomics.com/

You sign up there, give your comic website adress and banner if you have one, then you get a voting button code, just like the one I have in my signature. People vote on it so it goes up on the toplist. The current position on the toplist is shown on the voting button. There are various other webcomic toplists, but this one I find my favourite.

(now u can freely vote for Guilty Gene plz )