I've created a couple public folders in 2007 beta 2, ran the mail enabling tasks in the shell, sent a test email, and they always bounce back as undeliverable, any ideas how I can get exchange to recognize those folders exist? Running a Get-Mailpublicfolder | format... gives me the public folder, shows me email addresses related to it.

what undeliverable message do you get? it may be something to do with the permissions on the public folder.

It just immediately hits the undeliverable Queue as an unreachable domain. The recipient e-mail system isn't accepting messages now. Microsoft Exchange will not try to redeliver this message for you. Please try resending this message later, or provide the following diagnostic text to your system administrator. Above is the error. I have given Default and Anonymous Contributor permissions.

Are you solve your problem?