We have two different mapping announcements, one from Bing and one from Google. Bing's is the most interesting, in that they launched WorldWide Telescope data in their mapping software. Google updated their Google Maps for Android app to enable search 'n swipe, a latitude widget, and other changes.
Bing's telescope feature works by going to Bing Maps, and simply panning the maps up to the sky. Here is a screen capture:
Bing has partnered to get a ton of data about the sky maps, to learn more about it click here.
Google released version 4.1 of their maps app for Android. This version updated search results page, added a swipe feature, added a Latitude widget, plus a Maps live wallpaper, and lets you switch easily between Google Accounts. For more information about this update click here.
Forum discussion on Bing at WebmasterWorld and Google at Google Mobile Help.