Those who read the Avatar script when 20th Century Fox made it available to download will have read a few scenes that took place on Earth, however they didn’t make it into the film, most likely to keep the length of the film down.
Well today BUF Visual’s (via io9) posted an image of Jake Sully (Sam Worthignton) laid out in a bar. Apparently he’d been fighting a guy who he saw beating up a girl. You can see the two men in coats who we saw at the beginning of the film while he was cremating his brother. They obviously find him there, and that’s when they ask him to fill in for his brother.
James Cameron said that all the footage that didn’t make it into the film will be on the DVD/Blu-ray, so we can see it then.