If you get a good answer to this please let me know, thanks MrMMills@onebox.com
(That Reads "Mr M Mills @onebox.com)
Here is my lousy and slightly uneducated answer:
My only thoughts are to shut down the Exchange services and copy the pub.edb, and priv.edb files (and even dir.ebd just in case you end up needing to do a full restore) to DVD. These are the database files that hold all your Exchange emails, And Public Folder Files. However, this would not allow you to view the data on that Exchange server.
Would it be possible to image your current Exchange server and inflate that image on an identicle server not on your network. Then anytime you had to view data from a past month, you could take the data from the DVD, copy it to the second server (be sure to run attib -R on the .edb files) and view it on that seperate box only. I realize you probably want anyone on the network to access it but this is the only solution I know.