While scanning through the various threads in the Flash MX 2004 forum, there was a question asking whether it was possible to tile a background in Flash. This tutorial is an extension of the answer I wrote for that question, and I think there are some interesting concepts in the code that may benefit you in more applications beyond simple background duplication.
This is a companion discussion topic for the original entry at http://www.kirupa.com/developer/mx2004/duplicatebackground.htm
