NyARToolkit Augmented Reality on iOS
In preparation for the Augmented Reality class that Jonathan Blocksom and I taught at the recent iPhone / iPad devcon, Using AVFoundation video capture, we modernized and completed the example found at morethantechnical.com using NyARToolkit (GPL) on iOS. It's a great example of the kinds of things we can do now that we have fast devices with cameras to play with.
Be aware that this code is GPL, which (among other things) means that you have to release any changes you make to the code under GPL and that this code cannot be used in a commercial project. There is also some speculation that the terms of using the App Store preclude GPL licensed projects as well. Caveat Coder.