Hi L.,
I have mixed feelings on the "bite 'em back" theory. I have seen it in practice (with, I hate to say it, my husband *gulp*) and sometimes it does work. HOW it works, though, is what concerns me: when it is successful, it works by instilling fear into the child and associating Mom/Dad/Whoever with pain. Sometimes it is just a temporary solution (esp. with very little ones), and sometimes it actually does the reverse: baby bites, Mom/Dad shows EXTREME attention with a big painful bite, baby remembers next time that "When I bite, Mom/Dad will get all upset and pay lots of attention to me!" Bad attention is better than no attention.
I know it is hard but you just have to be firm and say either "No bite!" or, if you want to stay positive, "Kelsey! We only bite food!" It could be tough for a while, but just like everything else it will pass. (Don't be surprised, though, if it suddenly returns from time to time...my youngest is 3 yrs. 5 mos. and he just started biting his brother again in self-defense!)
Good luck and remember to offer plenty of good crunchy foods and chew toys to bite :)
--M.