This is really neat. The folks at Design Commission have produced a stencil to assist with the iPhone/iPod touch UI prototyping, brainstorming sessions, flows, interaction techniques, etc. that you'll do before you begin coding.
Of course, it includes all the standard iconography and buttons. Doesn't it make you want to just break out a fresh sheet of paper and set to work? If you want one, act fast, as they've only produced 100. Each kit ($16.95US) comes with the stencil and a Zebra mechanical pencil. A matching letter-sized template can be downloaded from the website as a PDF.
Now go and make the next killer app!