At a financial conference call last night Ubisoft's Yves Guillemot confirmed that Assassin's Creed III will be released on October 30 this year (via Joystiq). According to Guillemot the game has been in development for three years, and is the most costly game in the series so far.
Naturally expactations are high and Guillemot believes that Assassin's Creed III will beat the sales of Assassin's Creed: Revelations that has amassed 7 million sales worldwide to date.