Fuzzy Nation by John Scalzi

Prospector Jack Halloway's smart mouth and disregard for protocol gets him into trouble with the mining corporation he works for on the day he finds an extremely valuable seam of sunstones on a backwater planet. Then he goes home to his treehouse (safe from the dinosaur-type predators on the jungle floor) to find a previously-unknown native species inside. If this fuzzy little ewok-type thing is sentient, all of the rules will change and the mining company will lose its lucrative rights on the planet. The stakes are high - and that makes for a page-turner of a story with a fascinating character at its heart. I stayed up 3 hours past my bedtime to finish Fuzzy Nation last night.

Similar to: the movie Avatar.