People who buy the PS3 version of Thieves in Time will get the Vita version for free (only participating retailers or on PSN). Of course, the Vita is able to do a few things to enhance your gameplay on the PS3 version of the game.
One of the things is being able to scan for hidden treasures, which is done by pointing the Vita at the screen, which display an X-ray screen. All hidden treasures will be highlighted in orange. When the player points at one of the treasures, it will send a relay to the PS3 version, showing an arrow to where the treasure is located.
Another feature involves using Augmented Reality to snap pictures of various objects in the game using the Vita. When these pictures are taken, they can be sold for money in the game.