We use one. I definitely think it has worked. He has 12 teeth now and most of the time, I have not even known they were coming in. You can order them from Amazon.
Blair was just talking about the one she got for Harry a week or so ago on her blog. She seemed pleased so far...I've been considering getting one for my kiddo(s) as well.
Yes, we use one as well. It isn't a fix-all pain reliever (imo), but there is a noticable improvement in Alex's temperment when we use it and he's teething. I bought ours on Babysteals.
Re: Amber Teething Necklace