Google was quick to respond and explained that the Maps app was blocked on the Windows Phone platform, due to the platforms inability to properly run the HTML5 based Maps web application.
Google now seems to have re-evaluated their decision and removed the previous redirection which takes Windows Phone 8 users to the Google Mobile website instead of Google Maps.
Head over to maps.google.com on your Windows Phone web browser and try it out for yourself. Sadly Windows Phone 7 users have to continue without access to the Maps web app, and we hope that Microsoft will someday reconsider and upgrade all Windows Phone users to Windows Phone 8.
source - The Verge