[iPhone God App] It was found using the BreakMeter actually

Shave strokes off your golf scores with BreakMeter! BreakMeter is a utility for golfers to aid in "reading the break" on a green (i.e., seeing the direction the slope of the green causes the ball to turn).

Golf greens are often deceiving to the eye; what looks like a break in one direction is often straight or in the opposite direction entirely! The BreakMeter uses the iPhone's accelerometer to measure the angle and magnitude of the slope in two directions then graphically displays the slope to the player in an easy to read format.

Using BreakMeter during practice, you can train yourself to correctly recognize subtle breaks on the green which means you'll make more putts!

For usage instructions, visit the BreakMeter home page at:

http://www.breakmeter.com/