How do I play CALL OF DUTY 4 ONLINE for PS3?

I just got my PS3, and COD4, and I set up the network account and such, but when I go under 'play online', it show's my user name, and no one under it, and I want to play online with people, I don't care if it's random's, so how do I do it.

(I have two option's, free for all, and teamwork, I click on it, but doesn't give me a option to join a group or play people)



Thanks. :)How do I play CALL OF DUTY 4 ONLINE for PS3?
when you click one you just have to wait for an available game to come up.

my user name is emerica_skate, if you ever want to play with online just add meHow do I play CALL OF DUTY 4 ONLINE for PS3?
buy a 360