Remote play? As in using the PSV as a controller for the PS3?
That won't be practical with most games considering the PSV only has no L/R 2-3...you're missing two buttons and two triggers.
Keep in mind, however, that certain titles -will- make use of PSN Cloud, such as Ruin. Save, exit, move, enter, load. Congratulations, you're now playing Ruin on the big screen!
...Or on that absolutely amazing dual-3D twenty-something inch PlayStation flatscreen...
I'm pretty sure someone who demoed the unit a few months ago said there was L3/R3 (I forget where I read it, sorry).
I wasn't meaning using the Vita as a controller (although the OP may have?) for PS3, but just to see how they can work together. In January Kazou Hirai and Hideo Kojima both spoke of the relationship the Vita and PS3 would have and how they'd show it at E3, but nothing really was shown/talked about, except "transfarring", which we've known about since January.