Is this a new function of TheTrip.com? I know there used to be (two years ago) a website doing the same thing but I can't remember if it was TheTrip.com. It was pretty good and would look for fares on 5 websites (ITN, Expedia, Travelocity and two others). After the initial test period three of them denied access to their site so I think that was the end of it.
It would be nice to have TheTrip.com trying it again but as Phil stated they need to make some major improvements otherwise it's a waste of time!!!!