The Google Maps API has TAMaps integrated in it which is from TechAutos and the basic functionality results in scrolling and zooming with location tracking through GPS.
Though it has above said features yet it is deficient in some features like address and POI searches, the capability of calculating directions and also not able to support for bookmarking favorite places.
The installation of this app requires ChevronWP7 tool which comes with the WP7 SDK. According to the Chevron team Microsoft can start discussing ways of implementing homebrew on the WP7 platform.
To know about how to download and install Homebrew app, go to HERE.