Are you trying to get flamed with posts like these?
Seriously he has said that if Avatar becomes a success , he'll make the 2nd and 3rd movie. However it won't take so much time because the tech is there now. He wants to upgrade is the speed of the animation and the performance capture.
The only thing that might slow dow the development of the sequel(s) is his adaptation of Battle Angel. Rumors are that Cameron is busy with early tests and if he's sticking to his plan he'll make Battle angel before Avatar 2.
He's pretty booked for the next 10 years making Avatar first , then Battle ANgel ,, followed by AVatar 2 , Battle Angel 2 , Avatar 3 and Battle ANgel 3