I have not seen Avatar yet.. I am planning on it, though. If you've seen it, or if you're thinking of seeing it, you should look at what the blag-o-web has to say about its sociological aspects. (Critically analyzing media: it's what I dig.)
When Will White People Stop Making Movies Like "Avatar"?
Intentions be damned, Avatar is racist (Pt 1)
More on race and racialism in Avatar (Pt 2)
Ohhhh ... That's what Avatar is about ... (Partly in response to the above)
Dances with Avatars
And, last but not least, TVtropes' take on Avatar.
ETA: Moff's Law: a response to all of those goofs who whine, "But whyyyyy do you have to actually think about art, and analyze it? Can't you just watch it and enjoy it?"
Again ETA: There's plenty of -isms where that came from! FWD highlights both race and disability fail.