My users are able to go to File > Open > Other User's Folder and view anyone's mail. What am I missing? I thought this was a simple setting somewhere but I can't recall. Please help. I can't give my users the ability to view the high-chieftain's e-mail! Thanks.
Probably you've granted all of your users administrative privilege at the server or site level.
Go to the Exchange Administrator program on your Exchange Server, go to the Properties of the server first and then the site and see if you've accidentally specified your Everyone group as having any permissions that they shouldn't have.