I haven't tried to get online to play
Battlefield: Bad Company 2 yet but there's been some issues with the servers for the PC and PS3 it seems. EA and DICE have
posted an update saying they just put out R5 onto the servers to try and alleviate some of the issues. Some people are experiencing disconnects as well as server browsing difficulties. I'm sure they're working as hard as they can to resolve these things and it's good to see the game's become pretty popular.
Just to put it in perspective, EA says that
Bad Company 2 had more concurrent users than
Battlefield 2, which has been strong for five years.