Brian Killen, GroceryIQ
I'm working on designing my second iPhone App, first was Grocery iQ, and I love this sketchbook. I also bought a metal template from another company. Didn't really like it because it wasn't "Real-Size".
After being asked to design some iPhone® applications, I started to search around for design tips and information. There were PSD files, stencils and other paper prototyping tools available, but I’ve always sketched my ideas first. After printing out wireframe templates on sheets of paper (and ultimately losing my sketches), I decided to design my own sketchbook.