Please read and enjoy this very educational article on how to work with your puppy to teach bite inhibition–written by Kristen Seymour, linked from Pupbox.com.
Bite inhibition is an extremely important skill for puppies to learn, and they must learn it before their jaws reach adult strength. They learn this skill through biting–other puppies and dogs, and us. Puppies and dogs will teach the puppy through yelps, avoidance, and maternal correction until the puppy learns to temper his bite pressure. We can teach them by following the steps outlined below: