outgoing email monitoring

[Matt Miller <madmillerx () gmail com>]

hi list.
I need a solution to monitor the flow of outgoing email traffic for data 
leak/security concerns. The two objectives that i have are:
-monitoring and reporting -  who sends, how many and where to?
-possibility to temporarily put outgoing all e-mail on hold for 
reviewing by admin/user and releasing for delivery.

Any suggestions?
Thanks

Matt