There is a product that archives SMS and PIN messages from the BES.There are two components to the product: an agent on the bes and a viewer you can install on your desktop.
You will be able to see Subject, date, time who sent it or who it was sent from.
And you will be able to see the actual text message too.
You can't see this from your blackberry, you have to look at the stuff from your desktop.
Go to:
Netcleanse - Messaging and Desktop Security: Retain For BlackBerry