The PlayStation Blog have listed the 'Cross Controller' feature as one of a slew of additions landing on the Vita when System Software Update 1.80 arrives this August, allowing players to use the handheld to control their PS3.
Divulging that the concept "lets you take advantage of PS Vita's rich features including the touch screen, rear touch pad, six-axis motion sensing system, and cameras", it can be used with any compatible title on the home console (LittleBigPlanet 2, for example).

Other changes include the ability to control the home screen - as well as elements within the Video or Music applications - via the system's buttons instead of touch, rear touch pad compatibility with the browser, playback speed control and repeat play for videos and the ability to carry iTunes, M3U8 and M3U playlists onto the Vita from your PC or PS3. The update will become available on the 28th August.

For the full list of updates, check out the PlayStation Blog.