Just in case you didn't get enough of James Cameron's Avatar and its upcoming two movies, the universe is expanding into the graphic novel market. The comics will cover "the time before, during, and after the events of the original Avatar film." So, it's basically a prequel and sequel all rolled into one or rather the stuff they couldn't put in the film. Of course, we're assuming those coming after the movie should be after the second and third movie, because that will just completely spoil the story for the upcoming films. 

Source: io9