I don’t know if this is useful, but it is neat. I really enjoy seeing how people integrate paper into their digital activities.
the folks at Labs.Boulevart were kind enough to put together sketchpaper versions of the iPhone. It's a free download (in PDF or Photoshop flavors) of just a bunch of images of the iPhone, left completely blank (sometimes with the MobileSafari and/or carrier bar on there) for designers of all kinds to sketch on and imagine with as they will.
Very cool idea, and the number of different setups and implementations they've thought of is impressive—just the kind of thing to get the iPhone creative development juices flowing.