Macenstein points us to an interesting video which claims to create a "holographic" effect on the iPhone by performing real time adjustments to the image based on rotation:
The application works by assuming a constant viewing angle (35-45 degrees), typical for when the device is placed on a tabletop. The 3d scenes perspective is warped using anamorphosis, the same technique used in Hans Holbeins painting The Ambassadors. This application does the exact same but updates dynamically.
Our only confusion is its apparent ability to detect rotational information on what appears to be a flat surface. Of course, it's possible that the demo was performed on an angled surface.
Update: It's not real:
"The iHologram app was not real. It was an illustration of an idea I had which I believe could work with the technology (combining anamorphosis and motion sensing). Unfortunately Im just an ideas person, I can show how things should look, but Im no hardcore programmer."