I'm not in favor of smacking dogs, either. I work for a vet and have been snapped at by plenty of hand-shy dogs. Don't crate puppies as punishment--you don't want him to end up like my friend's dog who howls constantly when she's crated because my friend missed the point and only puts her in there when she's too rowdy. (I'm all for crate-training, though--my dog sleeps in one because she likes to browse through the garbage at night; but I can also put her in there if we have small, dog-shy kids over, and she never freaks out at the vet's or the kennel because she knows she's not being punished.)

If he bites too hard, yell (not at him, but "in pain") and stop playing. Walk away, taking all toys with you--giving him a chew toy is "rewarding" him. He needs to learn that if he bites too hard, the fun is over. Eight weeks old is pretty young so it might take him a bit to get the picture.

If dominance becomes an issue, another friend of mine cured his German shepherd by locking the dog in the bathroom for a few hours when it got too aggressive (the idea being that the dog can't be an alpha if he has no pack). It works better for some breeds than others--I grew up with American Eskimos and they HATE being isolated.