here's some of the new multiplayer footage. UC2 had a great online multiplayer but I never played it much cuz of BC2. The only thing about UC2's online that I didn't like was the third person perspective. Other than that, it was really good online play with some of the best graphics you will ever see. It had tons of DLC and cool modes to play. There was a pretty good progression system and voice chat worked great too.
If you wanna know more about UC online play, hit up RedFatality. He played the hell out of it.
IMO, UC3 will be one of the best games ever made. You have to play this game... after you play UC2 of course.

here's a vid of UC3 online play:
http://www.ign.com/videos/2011/06/03/uncharted-3-drakes-deception-hunters-mode-video?objectid=94314here's some more vids on IGN:
http://www.ign.com/videos/games/uncharted-3-drakes-deception-ps3-94314joystiq's articles on UC3:
http://www.joystiq.com/game/uncharted-3-drakes-deception