Ubisoft has confirmed its intentions for a new Assassin's Creed game (no, we're not sure if its going to be called '3' yet) during its Q3 investors call earlier today, and says multiplayer will be apart of the game.

During the call, among other things discussed, Rome will be the new setting and our friend Ezio will be there, fighting his way through the city to act against the Templars.
Multiplayer was also mentioned, where players can participate in an assassination mode against friends and others online.

So far that's it. No date, and no official name, but we'll have more info as it rolls in over time.