Forget the iPad for just a moment. According to The New Media Consortium's 2010 Horizon Report, simple augmented reality is two to three years away. One of the possibilites for using that technology is in augmented reality textbooks, which essentially bring the animations in the opening credits of Reading Rainbow into the real world.
The report's section on simple augmented reality reads:
Augmented books, now just beginning to enter the market, are another interesting application of this technology. The German company Metaio is developing books that include AR elements, such as globes that pop up on the pages. The books are printed normally; after purchase, consumers install special software on their computers and point a webcam at the book to see the visualizations. The technology allows any existing book to be developed into an augmented reality edition after publication; an atlas featuring 3D views of geographic locations is currently in development.
To get a visual idea of what Metaio's efforts may culminate in, check out this demo from Thailand's Institute for the Promotion of Teaching Science and Technology. It shows a female student thumbing through a textbook on geology, learning about the different layers of the Earth.
Pretty cool, huh?