Since I'm on garage-sale eve here, I have no time to write, so it's another fun link.
But this is a big one! PhD in Parenting is a great blog I recently added to my Google Reader, and here its author puts together what AP is NOT, which I thinks help explain what it is. So many articles lately seem to be conflating AP with the hothouse/helicopter/status-driven/trendy/be the BEST parenting style going on lately... and that's not true at all. I think APers tend to be more laid back. So here it is, in much better words than my price-sticker/newsprint/hauling furniture brain can summon right now:
Attachment Parenting: What it is and isn't