I've heard the following from a few places, including the woman who teaches my obediance class, on bite inhibition:
When the dog is play biting and bites hard, yelp (like a puppy) and walk away from the dog. Keep working at it and yelping on the hardest bite, even if its not hard, until the dog doesn't bite at all.
Dogs are supposed to learn bite inhibition from their mom and their litter mates and usually have a problem with it if taken away too soon. So it's up to the new owner to teach the same.
I've been doing it with Harley and I am pretty sure it is working. She no longer bites my roommate at all, and she only bites my hands when I ask if she wants to play. Sometimes she does get carried away and bites hard. I say "ow" in a high-pitched girl voice (no offense
) and pull away. Then she'll act like she wants to bite, but stops and licks instead.