The earlier Windows Phone 7 Bing Maps control allowed you to obtain an API key and use it during development. This process has changed for the new Map control. You now obtain the API keys for your app, at the last minute, as part of the Windows Phone marketplace submission process.
AuthenticationToken values are specific to your app and are retrieved after you have provided a name for the app, at stage two of the marketplace submission process. On the Windows Phone Dev Center website, follow the Map services link and click Get Token. The new
AuthenticationToken are displayed on the same page. Copy and paste the values into the Map object’s
Loaded event ...