Here are 5 Signs Your Baby is Teething from Dr. Sears:
I was told to buy Hyland's Baby Teething Tablets to help. Also to get an amber teething necklace, which I had planned to buy but didn't realize I'd need one so early! I'm going to order it today. Or right now, from Inspired by Finn. Some other suggestions were freezing a pacifier (he doesn't take a pacifier, so nope!), freezing a washcloth, which is a good idea, I tried to give it to him but he made a face at me so I'll try again later. One thing I found sounded really cool! You pump a little breastmilk and put it in a bottle nipple, then stick a pacifier in and it makes a "momsicle" haha I think I'll try that later on just because it's funny.
Kellymom also has a good article about teething here. Including what to do about biting while breastfeeding, sore nipples, and if your baby refused to nurse due to pain.