According to this blog posting by photographer, Falk Lumo, the camera in the iPhone 4 is a 3.85 mm f/2.8 lens.  The 35mm film equivalent is 29.4 mm f/21.4.  If his information is correct that would mean the iPhone 4 camera has a wide-angle lens with a large depth-of-field (DOF).  Not great for macro photography — as I already discovered.  I’m considering getting one of these macro lenses from Photojojo.

Falk Lumo: Apple iPhone 4 camera specs, %name