360:
Download content, including dashboard themes, gamer pictures, game trailers/demonstrations, movies, game content such as new maps, weapons, levels, characters, challenges, expansions, arcade games and demos; connect with friends/players via voice chat, video chat, instant messenger and text message. Friend's list, clans, matchmaking, lobbies, leaderboards, and achievements. Then the monthly fee is to actually play online.
PS3
All of the online services, (Account created through user registration, Lobbies/Matchmaking, Scores/Ranking, Game data upload/download, friends list, Voice/vid chat, messaging, web browser) are free, as is normal multiplayer gaming. The only things that aren't free is paid-for downloadable content and subscriptions to premium services, such as massively multiplayer online games.
Everything is from wikipedia. Is the online service actually hosted by Sony or is it gamespy and maintained by the company?