3 year old out of control..?

Sounds like you might need SuperNanny! You're on the right track. Consistency in your discipline, you know, is the key. I'm not sure that smacking hands or is getting your point across, only shows him that it's ok to hit. Get on his level everytime you have to discipline him and tell him why it's not acceptable behavior. Putting him in time out will eventually get to him. Don't give up! Try to occupy his activity to keep it productive and positive. Praise his good behavior! GOOD LUCK!