Filed under: Cellphones, Portable VideoSony just revealed a bit more about AT&T's Mobile TV service launching in May. We now know that one of the two exclusive AT&T channels will be called PIX, Sony's new feature film channel for cellphones. The service is a first of its kind in the US for good reason. Oh, it's not that we have anything against the roster of films including "Ghostbusters," "Philadelphia" and "Karate Kid." It's more the prospect of sitting in front of that tiny mobile screen to watch a fu