The PlayStation Blog has posted some details about the campaign, including some specifics on locales -- even an eight-minute video walkthrough of some campaign action, some of it sections we have already previewed. Hit the jump for that video.
As for multiplayer, the post talks about class freedom (you can be a sniper medic, for example) and some of the unique unlockable abilities, though what each one does isn't specifically detailed. Expect a multiplayer beta to go live "later this year" -- nothing more specific than that, though. If you picked up SOCOM 4, you can just sit back, relax and ... wait.