Copying all outbound exchange mail

I have a need to get a copy of each outbound exchange e-mail and store it in a unified directory whereas a single "administrative" user can look over the mails content. This directory where the mail is stored will have secured access limited only tothe "administrative" user.

I prefer to use native Exchange 5.5 or NT 4 to acomplish this task. But I am not adverse to third party solutions.

The solution sought is not to prevent/delay mail from going out but only make a copy to review and archive.