Augmented Reality is set to be a big thing assuming people can find good uses for it. There's a PS3 game called Eye of Judgement that works using a similar technique.
I saw a similar thing on the Gadget Show a few weeks ago, they were demonstrating it as an educational tool. For example, you could bring up a model of a skeleton or a human body and move it around in 3D to examine it, obviously useful for medical patients or biology students. They had these books which had a sort of barcode on the page, and the computer reads the barcode and brings up the relevant model on screen, and of course it can see what angle the barcode is at and hence what angle the model should be at. Really simple when you look at it.