Here's some useful information from the documentation team:
The recent release of the Windows Phone Developer Tools January 2011 Update includes bug fixes, a new emulator, and utilities. Alongside the release of the tools we have also published an update to MSDN that focuses on documenting key aspects of this release, known issues/limitations and additional content for developers. The highlights of this release are listed below and also available in the What’s New topic on MSDN.
§ NEW DOCUMENTATION
§ Keyboard Input Scope Sample
§ Model-View-ViewModel Pattern Sample
§ Silverlight Sound Sample
§ UPDATED DOCUMENTATION
o Bing Maps APIs are now included in the class library reference