Yup DS went through that stage - he hasn't done it for a few months now.
The first time it happened I smacked him cos I was so shocked!!! Not to mention it bloody hurt!!!
Then after that, (and I started up a few threads about it on here) when it happened, I would say "OUCH" and "NO" really loudly and pick him up and put him in the middle of the room away from all his toys and walk away. He would cry, and then try to follow, but I would put him back in his spot and make him sit there for about a minute by himself, and then I would pick him up and give him cuddles and tell him he was very naughty for biting mummy and not to do it.

Must of worked cos he sometimes goes to bite me, but I see him coming now and say "No" and he backs off...