Alternative on Android.
An alternative exists on the Android Market already: http://www.starreservoir.com/ it uses either the GPS (if enabled) or 'rough location' from cell towers, and the compass on the G1 to get the right location and orientation.
It works pretty well, and is nice to see what's above you (and prove to your annoying "know-it-all friend" that it is Betelgeuse above you)