The first thing you have to do is get this dog a complete check up to rule out any physical problems. Once any health issues have been ruled out you need to do some serrious obedience training. If you have a PetSmart in your area, you can check out their class schedule and fees, I believe that they are quite reasonable. Also, as others have recommended check out the Ceasar Millan materials that are available to you. You cannot play any tug games with him. Any games that involve biting or chewing have to be stopped immediately.
I agree this is probably a dominance issue and this little fellow has to realize that his place in the pack is below your wife and children.
Good Luck with correcting this behavior.
__________________  Joan and The Heartbreaker Trio:   Little Paws Leave Big Prints |