iPhone 4s Stereo Camera Adapter
This is an adapter that fits over an iPhone's built in camera. The camera's view is split into two parts with adjustable mirrors to find and set the appropriate angles.
You'll need two of these (19mm mirrors)
http://www.edmundoptics.com/optics/optical-mirrors/flat-mirrors/4-6-first-surface-mirrors/46-652
and two of these (38mm mirrors)
http://www.edmundoptics.com/optics/optical-mirrors/flat-mirrors/4-6-first-surface-mirrors/46-650