Trailer: http://ve3d.ign.com/videos/play/74149/PC/Assassins...

Images (sorry if old): http://www.gamesradar.com/xbox360/assassins-creed-...

So awesome!
Such an dark and badass music intro when Ezio shows up, fits the character perfectly.

Info from a magazine

-Singleplayer follows Ezio who's 45 now trying to rid Rome of the Borgia clan.
-Cesare Borgia is the main bad guy. He's the son of AC2's main villian.
-Game takes place entirely in Rome. Rome is 4 times the size of Venice and is divided into 4 districts.
-Ezio can recruit characters off the street to aid in missions. Experience points can be spend to build up their skills.
-Combat is mostly the same but the player can now chain kills together in rapid succession.
-Collectible items and secret location challenges return.
-The meta game of building up the Villa in AC2 is now the entirety of Rome.
-You can do assassinations from your horse now.
-Leonardo Da Vinci is back along with new and returning gadgets.
-Multiplayer is separate from singleplayer but the story crosses over into both.
-Multiplayer will include adversarial, team based, and objective based modes.
-Multiple classes with unique weapons and assassinations.
-There's a point system which allows you to upgrade your multiplayer character.
-Adversarial mode drops 6-8 players in a map where your assigned a target to kill. Another player is assigned you as the target. So there's a constant cat and mouse going on.

Sounds fantastic IMO, I hope we see gameplay at E3, having posses or enemies that are assassins as well in a AC world would be awesome.
I also read that through progression you are able to start customizing your character with outfits, colors, weapons...etc.

Ezio still has his beard LOL :P

On the cover there is a girl, but I would think its more of an class than pick gender and then class.