Exchange-Mailbox-Monitoring is a project mainly written in ..., it's free.
Using public folders to make a copy of all mail sent to/from a user
This Powershell script will allow you to create a public folder ($pfolder) underneath a specified "Mailboxes" public folder, and set up transport rules to BCC any messages sent to/from a user to this public folder. It also analyzes the SCL of incoming mail, and places all SCL 9 e-mail into a "Junk E-mail" subfolder.