I also agree. A user should have the ability to view Private Messages sent between users. The Kiddie Porn Example certainly shows why Private Messages should be monitored. And this way we could warn users about the messages they send.
If the Administrator or Moderators have the ablity to read PM's then it should also be Displayed on the Private Messages page. "Messages that you send to other users may be monitored for security purposes!"
Borg what do you think? Would you be able to implement an Administration of Private Messages for v8?