If there's one thing that Google Earth taught us, it's that the stars never outgrow their mystery. For fans of the sky layer on Google Earth, there's Starmap, an educational iPhone app that, unlike your laptop or desktop, you can easily take with you on a cloudless night to a nearby hilltop.
Pocket astronomers will find a screen that shows a sky full of planets, visible stars, named stars, galaxies, and nebulae, and coordinates that you can access and search for from an unobtrusive ribbon of icons. Sensitivity to the accelerometer tips the view vertically and horizontally, and you can pinch and pull the screen to get a closer look at the arrangement of the points of light.
It's a fair and interesting start, if not a bit static, and the land-locked dreamer in me sees many more interactive possibilities as the tools and technology progress--like a real-time night mode that uses the camera as a telescope to automatically fix the star chart around you and a Wikipedia plug-in that spoon-feeds you information about what you're looking at. You know, the kinds of extras you'd expect from Google Earth.