What I believe is meant is how to monitor the content to/from the SMS applications available through the iTunes store, which enable full texting capabilities when connected to an active wireless connection.
I would like an answer to this question as well. There are apps available through subscription fees that will do so, but such a capability to limit or even monitor should be integrated into the OS run on the Touch/iPhone.
The only way to 'monitor' activities in third-party apps is to run the app in question. Some third-party apps support Notifications which pop-up a message on the screen notifying you of some event.
You'd have to read up on the specific apps you are considering to see whether they support Notifications (which are built in to the OS).