According to Variety, FX has acquired the basic cable rights to James Cameron's Avatar.
The terms of the FX deal weren't made known, but it looks like FX ponying up an estimated $25 million-$30 million. That's higher than the cable company normally pays, "but due to the nature of the movie's global gross and demand from other networks, Fox was able to get a substantial increase."
FX can begin airing Avatar around the middle of 2012. They will likely have a window that goes toward the end of the decade. Deals like this usually last four years, but negotiations allowed for the window to be extended.
Due to its output deal with Fox, HBO is going to have the pay cable rights and will air Avatar before FX.