Well, I'd agree with Lucy...I'd spank my kids, too, for biting. But, if that doesn't work on your child, or if you don't believe in spanking, then I thought Dr. Phil gave some good advice about it on his show a few weeks back...
here's the link and I copied and pasted below :
http://www.drphil.com/advice/advice.jhtml?contentId=par_raising_dillemas.xml§ion=Parenting&subsection=Raising%20Kids
Biting
Miren and Scot's 19-month-old son is going through a biting phase. How can they stop the behavior before someone gets hurt?
<LI>Remember to use age-appropriate discipline techniques. If time-outs don't work on your child, it may be that he's too young.
<LI>Be aware of your reaction to being bitten. It's a powerful reward for a child to know he's gotten mom and dad's immediate attention.
<LI>Kids explore with their mouths; it's a communication tool and it can be effective for them.
<LI>The first step is response stopping. When you see the child getting frustrated, opening his mouth and preparing to bite, you have to immediately get his attention and stop him. That means eye contact and saying with authority, "No biting."
<LI>After response stopping, you want to redirect. Physically move your child to something else, to distract him from whatever was making him want to bite. When you disrupt the sequence, then he's out of the impulse.
<LI>Communicate for your child. Tell him what you know he wants, so he knows you understand. "You're mad because you want that toy. You want that toy, don't you?" Don't give him what he wants, but telling him what he wants makes him feel he's understood.
Never bite your child back. You may suppress the behavior instantly, but it's confusing to him and the child may have a bad reaction to that later.
Good luck!