Get the videos by Dr Thomas W. Phelan called 1-2-3 Magic on encouraging good behavior/managing difficult behavior in children. It WORKS!!!
Then look up Maslow's Heirarchy of Needs, study it, and see where his needs may not be being met.

Sorry for your troubles. I'm no expert but just wanted to share...

he'll know he's well cared for and loved by experiencing your boundaries. set them lovingly but firm and don't budge, give a reprocussion *every* time he misbehaves -- he'll know what's expected of him and know you care and you should see improvement. good luck!