http://popapp.in/
Design on Paper
Creating wireframes on your favorite notebook. Take your time and sketch your interface carefully. Pen & paper are the best tools. Complicated software only gets in the way.
Take Pictures
Import your sketches by taking a picture. POP automatically adjust brightness and contrast to make sure your sketches are legible and clear.
Simulate
Create a storyboard by linking your sketches together with “link spots”. Press play and simulate your user interface to make sure everything flows correctly.