I just downloaded the first Microsoft application for the iPhone: Seadragon. I just started to play with it, when I saw that, among the images you can use to zoom in and out that come with the application, there is the stunning Eta Carinae Nebula! Not to mention the many other astronomical images. The speed at which Seadragon displays the images is really stunning. A little faster than the Google Earth plugin, but so cool for a little device like the iphone. Well done.
Check it out: seadragon