PCT = post cycle therapy. Here are a couple links that will help you understand some of the basics, followed by a link to the pct forum:
one8nine's opinion on pct
http://forums.steroid.com/showthread.php?t=354573
Swifto's pct sticky
http://forums.steroid.com/showthread.php?t=349581
Pct forum
http://forums.steroid.com/forumdisplay.php?f=77