TargetVision is now selling something they call the Universal Picatinny Phone Mount. This aluminum device allows a shooter to mount an iPhone or similar device to a gun for the purposes of recording photos and/or video.
The unit allows a great deal of flexibility in the size of device it holds. Additionally, a ball head allows for nearly infinite adjustments to get the angle you want.
The unit weighs 0.3 pounds and sticks out about 4.75 inches from the side of the firearm.
The MSRP is $150.
TargetVision also sells a portable target changer and wireless target camera.