The folks over at ARToolWorks look like they’ve got a version of their software running on an iPhone. Since the iPhone SDK doesn’t provide access to the camera for video, I assume they’ve done it using a hacked phone. Speaking of ARToolWorks, they’ve got quite the team over there. Mark Billinghurst has always been an evangelist and Philip Lamb does great wpork with the actual code and infrastructure. Daniel Belcher and Raphael Grasset are both talented AR researchers and developers, too.
httpv://www.youtube.com/watch?v=5M-oAmBDcZk

