Heh, this looked like the Legal Trap at first, but I guess this works too. In fact it's probably better than the Legal Trap in this case, since using the trap would require 1. ...h6 2. Bh4 first, and there's no guarantee White will play 2.Bh4.

EDIT: Oh, you can't do the Legal Trap here...Nxc5 removes the threat.

This is one of my favorite tactics, I pull it off quite often.

I fell for this when I was playing from the computer (I was playing the English). When he took the pawn, I saw what was about to happen... but I couldn't stop it!