Producer John Landau was attending a screening of Titanic 3D when he had the chance to speak about the upcoming Avatar
sequels, and said that they are "four years away". The plan is still
to shoot parts 2 and 3 back to back. So this could mean 2016 or
Christmas 2015 for the first sequel. It seems like from comments made
by Sam Worthingon and even James Cameron himself recently, that they
were getting ready to start filming as early as Fall 2012, for a
Christmas 2013 release, but maybe not. Whenever Avatar 2 begins, we will keep you posted!