Remote Play is one of the supported features with the Playstation 4, where you can use the PlayStation Vita to play PS4 games on its screen instead of the television. This is done over Wi-fi networks using the PS4 Link and it will also require the Vita system software update that will be released close to the PS4's launch. Note that not all of the PS4's titles will be available for use with the Remote Play feature.
Second Screen
Some titles support the ability for the Vita and other devices, such as smartphones and tablets, to be used as second screens in them. For smartphones and tablets, this will require the Playstation App to be downloaded on them.
One example of this function in use is with the pre-installed title called The Playroom. This requires the PlayStation Camera, and the user can draw pictures on their devices. These pictures can then be flicked towards the television, where they will appear as 3D objects.