You just need to set a retention policy on the public folder.  Check out the limits tab on the public folder properties page in the exchange system manager.

Bill

Is it possible to include Public Folder in the Mailbox Manager?  I want to automatically delete messages after a certain date.

-Devon

This message (including any attachments) is intended only for the use of the individual or entity to which it is addressed and may contain information that is non-public, proprietary, privileged, confidential, and exempt from disclosure under applicable law or may constitute as attorney work product. If you are not the intended recipient, you are hereby notified that any use, dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, notify us immediately by telephone and (i) destroy this message if a facsimile or (ii) delete this message immediately if this is an electronic communication.
Thank you.