Robin Debreuil has announced a beta of Viewer Screwer, an ActionScript obfuscator.
Viewer Screwer is an Actionscript Obfuscator - a program that takes your actionscript and scrambles it into something that can only be understood by a computer, not a person. You can scramble individual files, or multiple files that must work together.
You can view the announcement here, and post questions to the forum here.
This could turn out to be very useful for Flash developers who want to protect their SWF code from prying eyes and hacking.