We dramatically updated our guidance around Windows Phone development. Beyond recompiling our previous guidance against the Mango SDK, the latest guidance takes advantage of many Mango features such as fast app switching, background tasks, and new sensor APIs. We also did a fair amount of work showing how to create a layer of abstraction on top of the Windows Phone APIs that facilitates unit testing.

We split up our guidance into three parts:

1. Developing a Windows Phone Application using the MVVM Pattern
   This guidance walks you through building a simple Windows Phone application using CodeBehind files. The guidance then shows you how the same app can be much more unit testable when built using the MVVM pattern.
2. A Case Study for Building Advanced Windows Phone Applications
   This guidance takes an in-depth look at how to write an advanced Windows Phone application, using many features of Mango. Unit testability was an important factor that guided the design of this application.
3. Building Testable Windows Phone Applications
   Taking the work on unit testability from the above guidance, this guidance provides shorter samples of how to build unit testable Windows Phone applications.

Please take a look and send me your feedback.