In a neat experiment, developer Colin Eberhardt shows how it is possible to import Google's Sky Maps into a Windows Phone 7 application, using the same mapping APIs as Bing. This is a popular trick that we've seen with TA Maps and other programs that access 3rd party mapping databases.
The downside here though is that this is far from what they have on Android--which is an augmented reality application used for discovering and showing celestial objects in the sky using the phone's compass and accelerometers. Instead, this just shows the Sky Map with some pre-defined objects for viewing. Furthermore, Google evidently is not allowing use of the data outside of their services, so we'll have to either wait for an official Google solution or some really ambitious home-coder.