I've heard that he helped with some space-videos with NASA.
Yes he does work with NASA, Since 2005, see this article for more infos:
Two years ago, not long after the Columbia accident claimed the lives of seven astronauts, Cameron attended his first meeting as a member of the NASA Advisory Council, a body that counsels the agency's administrator.
Slowly, he became more engaged. Now, he's working as an investigator on a camera for a Mars mission set for this decade.