PS3 and Vita can already share saves and whatnot, but according to Sony Europe R&D Manager, Phil Rogers, the to can communicate much more. At the Develop conference, Rogers stated that "PS3 can send data down to Vita and Vita can display it." He added that "You could use the unique features [of Vita] – gyroscope, touch front and back – as a control for a PS3 game."
This sounds very similar to another little device that caught our attention a few months ago — Wii U. Vita will have some cross-platform features, including scoreboards and PSN user data.
Remote Play, also available on the PSP right now, allows video of compatible titles to be streamed from the PS3 for play on the PSP. Continuation Play, through which a game can be saved on one platform and played on the other, will also be available early on. The first known game to use that is Ruin.