I'm about to start using this, because I really like the idea of getting the feel on the iPhone itself. However, I didn't see any preset components included in Protoshare that are specific to the iPhone like you have for the web. This seems like the first thing to get going--all the iPhone-specific components should be in their own Components pane. The great thing about the iPhone is how relatively few of these there are, and how standard the sizes are, leading to a very consistent experience: scrolling lists, cover flow, dialog boxes, etc. So I'd rather not adapt raw boxes, etc from the web components when I could have iPhone specific ones.
It's tempting, of course, to include Photoshop background images of all of these components as well, although that takes us away from the wireframing concept.
Thanks, keep going!