The pubCenter BETA forum is currently available only to registered users of the pilot program.
If you are an approved participant in the pilot program, information on how to register for the forum is available via the pubCenter BETA help: http://go.microsoft.com/fwlink/?LinkId=111312
If you wish to help test pubCenter, please submit information about your interest at http://advertising.microsoft.com/publisher
We are currently seeking to expand the program to quality small and medium Web sites in the US.
-Chris
Chris Norred, online community program manager for Microsoft adCenter, API and publisher programs.