I just read the following tweet "RT @VentureBeat: iPad 2, iPhone 4 gets glasses-free 3D using head tracking (video) http://bit.ly/gg2OEw". You guys should check out the article it's about some researchers that have been able to make an iPhone 4 and the iPad 2 display a 3D view of an object.
The idea is that the front facing camera looks at how you are looking at a screen and renders based on that. So if you move your head it changes the coordinates and viewing vector of the scene camera. Now that's pretty amazing tech