This question is asked every week on this board, so you can find at least 100 posts answering this question when doing a search here. The question is no sooner asked and scrolled to the bottom of the screen when it appears again. It is very popular.
Polybutylene Information Help Site – 5 STAR SITE – http://www.polybutylene411.org
Terry Love Plumbing Bulletin Board – 5 STAR SITE – Info on Repipe – http://terrylove.com/pipe.htm