You probably can't watch it from anywhere yet unless somebody was able to discreetly record that entire movie from the SquareEnix booth at the Tokyo Game Show. I doubt you'll see anything for a while. Check google video, you tube, and anything else you can think of to see if anybody posted anything yet.

Btw, did I mention how GOOD the music was in these games? The main theme they used during FFXIII was better than anything I've heard ... well ever. It's really engrossing and empowering along with the gameplay.