I'm not sure this is new, but it's dangerous!
Email scam targets Facebook users: Web security firm - Yahoo! Canada News
Essentially, you get an email that looks like it's from Facebook. It tells you your password has been reset and you need to click on an attached file to retrieve it.
We all know NEVER to click on an attached file unless we know what it is, right? (And by "know what it is", I mean we know who sent it AND we were expecting to receive something from that person. If the other person's computer has a virus, they might send you a file accidentally.)
I figure we all know. But this also seems like a good time to remind you. :)