Read original post by John Kimani at AfricaApps
Windows Phone 8 contains a new Maps API that is different from the Bing Maps available in Windows Phone OS 7.1. One major difference between the two controls is that the WP7 control is a Silverlight control, while the new WP8 control is native and hence part of the WP8 SDK libraries. Another difference is the fact that the WP7 control was based on Bing Maps while the new WP8 control is based on Nokia’s Here Maps. However, the old WP7 control is still supported on the WP8 SDK but is deprecated and is only recommended for upgrading WP7 apps to WP8.