This is one application I have developed for WP7. It is a map of the night sky and at the same time a three dimensional map of the nearest stars. You can switch between a view from the Earth and a Space view of the nearest stars. A 3D view of the solar system is coming soon. This is a link to the Windows Phone Marketplace:

The website for the project is

A short introductory video can be found on YouTube at and also another one at