Paper prototyping for the iPad is super easy, especially when compared to other platforms.  For web-based prototypes, you often have to incorporate a mouse and keyboard.  And for the iPhone it can be tricky to approximate the form factor yet still keep everything legible.  The iPad has the best of both worlds: ample screen space and no fussing with peripherals–unless there’s an external keyboard.  Here are some examples of iPad paper prototypes; I’ll update the list as I find new ones.

OmniGraphSketcher: http://bit.ly/9aLU9a (see image below)
NPR: http://www.snd.org/2010/04/inside-the-design-process-for-nprs-ipad-app/
Instapaper: http://www.marco.org/357350758

Found some other great examples? Send them my way!

OmniGraphSketcher for the iPad.