I'm not up on the subject, but last time I checked MGS4 was going to have a separate multiplayer component, as in stand-alone, You'll have to buy it. They might've changed that config around by now, i dunno.
It looks cool, I don't think I like the blue HUD indication for your comrades though.. the max will be 8 vs. 8, I believe. They bring back the snake vs. bad guys as well.