Google 'Game Battles' and click on the first link. This'll take you to a site where you can register teams for online games and win prizes. I'm not sure how they all work, I've only see the Ghost Recon :Advanced Warfighter 2 page, but you can set up a team or become a 'Free Agent' so that people can invite you to their team. You can set up your account to show your Live Gamertag, PSN ID, and/or Wii friend code. You, as far as I know, can also win cash prizes aswell.

Oh, and the button at the bottom of the Join Page isn't broken, just click it once or twice on the text.

It certainly looks interesting. I've made an account there.

This is quite old. I used to do this for SOCOM II. gets annoying after some time though.

It really depends on what you're playing really. I'm not sure if you've noticed, but look at my sig. You can get 'cards' for your team on there aswell.