http://boardsus.playstation.com/playstation/board/message?board.id=ps3&thread.id=4167541&view=by_date_ascending&page=1
I'm getting the exact same problem. I play MW2 Multiplayer, and at the end of a match the scoreboard is shown and my PS3 freezes. This is happening to me every 2-3 games after resetting the damned PS3. This isn't as harsh, but in that link people claim that MW2 is truly screwing their PS3s up. This is fucking annoying.
Who else is having this problem?