Biting is a really common, but fortunatly temporary, problem! And it really, really hurts!!! It's a bit like stubbing your toe: overwhelming pain, but it fades. There are some fantastic ideas for overcoming it here:
http://www.llli.org/FAQ/bite.html
and here:
http://www.llli.org/FAQ/teeth.html .
Both of my children have bitten me while feeding, but luckily it hasn't meant the end of the breastfeeding relationship. It was a hurdle, though!!! And it did hurt!
Mums who decide to wean because of biting need to be very careful to reduce feeds gradually to avoid plugged ducts and mastitis; and that may well mean that in reality the biting phase is over well before the milk dries up; so in fact, they can carry on feeding....
Melanie