We mentioned a few weeks ago about a proof-of-concept when it comes to Windows Phone 7 and Google Maps, namely that if Google didn't do it (and do it soon) someone else would because it's very easy to redirect an app towards Google's map servers.
Looks like Tech Autos has accepted the challenge and released a simple but fully functional Google Maps application. The app right just brings down the maps and shows your location, so not too useful. But the developer plans to add Address / point-of-interest search, Directions and Favorites, making the program much more useful.
The bad news: You have to have your phone unlocked/jailbroken as a developer or by using the now defunct ChevronWP7. The latter is more difficult because you actually need a certificate that was hosted on their servers. Luckily XDA has your back on that one.