It sounds like the release date of the second Avatar movie has been pushed back yet again. At a press event celebrating the rerelease of Titanic albeit in 3D this time round, producer Jon Landau said
"We're not naming dates, but I think 2014 will be a tough date for us to make. For us, it's about getting it right. Titanic was supposed to be a summer movie; it was a December movie. The first Avatar was supposed to be 2008; it was 2009. Movies make release dates; release dates don't make movies. We're going to get it right."
Though he did confirm production was underway on the movie, which is meant to be predominately set under the oceans, he did confirm that the whole movie would not be set underwater
"The underwater thing - to put it into perspective - I believe that the best way to look at it is it's going to be like the floating mountains in the first movie. It's not going to be all underwater. It's going to be a place that we go to, come out of, go back to; that type of thing."
So judging by his comments it may be a safe bet to expect a second outing in the worlds of Pandora in 2015.