The TGS demonstration was actually done via a wired connection between the PS3 and Vita. This was necessary because of the high volume of people at the event potentially causing interference. Yoshida promised that in more realistic circumstances, you'll be able to play wirelessly at the same level of speed shown at the event.
PS3 titles that are played via Remote Play need a bit of customization for memory and CPU use. Sony is finishing up work on a library that facilitates this and will be sending a beta version of this out to developers to test upcoming and old titles.
While Yoshida did not say when Remote Play support will be ready for PS3 games, Vita owners will get to try out one area of Remote Play at launch. Sony is finishing up work on the required customizations for Torne, a popular first party device that gives the PS3 digital video recorder capabilities. Following a December update, this will support Remote Play on Vita.
Outside of pure Remote Play, Vita can be used as a controller for your PlayStation 3. The system's screen can also act as a sub monitor. Yoshida said that Sony is looking into creating utility libraries that will allow PS3 developers to use the Vita's touch screen. (andriasang)