The Bike Mount for iPhone designed by Purligar lets you attach your Apple iPhone 3G / 3GS to your bike’s handlebars so you can track your GPS position, your speed, or distance travelled while you ride. Or perhaps you could use it to video your downhill ride, but not for watching videos during same said ride.
The bike mount is designed for bikes with 1" (24-26.5mm) handlebars and
works in bot portrait or landscape mode. It has been field tested and
used during the last months by several people. Possibly used in
combination with the Road Popper?