I currently swap (mainly ATC's) on 2 websites under the name of neca84
www.swap-bot.com is a fun swap site where you can join groups for group swaps or one on one swaps.
www.atcsforall.com is another great swap where people host swaps and all players send to them and then they return all the cards out to all players. I have sent in about 7 of these swaps but as yet havent received any.
Whoops for those that don't know and most of my friends and family wouldnt know ,,, ATC's are Artist Trading Cards,, these cards uniformly measure 3 1/2 inches by 2 1/2 inches and are traded OR given, they are not supposed to be sold. A better explanation can be found at http://cedarseed.com/air/atc.html