Go to the HeroClix section and click How To Play for the rules and such. There will also be links to the FAQ. Sign up for an account there for signing up for tournaments, and then you can search for venues in your area on thier site to find out who is holding events near you.
I looked where you suggested but it was quite confusing. There is a rules document, a quick play set of rules, there are rules that seem to be just for certain expansions. I wanted to make sure I could read up on everything I needed and not miss something.
I know you are looking for down-loadable rules, but I'd highly suggest going out and purchasing a Marvel Universe Starter from your local store. It comes with two preconstructed teams and a complete rulebook (plus action tokens, dice...).
Don't worry about the FAQs until you have a few games under your belt. If you are really looking at joining in tournaments, I'd suggest going to your local venue and talking with your local Judge...or if your close to the IL/IN border, come on over to the Clix For A Cure event in mid-May being held in Bloomington IL. There will be plenty of us there to help you learn the ins and outs of the game.