The upcoming Vita release of Hatsune Miku Project Diva f 2nd will come built in with a cool feature for the handheld. Markerless AR capability.
This means that Hatsune will be able to perform anywhere in the real world without the use of any AR cards. The previous release last year came with the same ability but required a card to project Miku onto a real world surface.
The new feature called AR Live will allow you to also change her outfit and select one of 8 songs to perform. Miku can also perform with some of her vocaloid friends as well.
You can join in with Miku and her friends when the game launches in Japan on March 6th for PS3 and PS Vita.