Silverlight for Windows Phone 7 Series allows you to take full advantage of your Silverlight experience to create mobile applications. Visual Studio 2010 makes it simple to design the UI and debug new applications that target Windows Phone 7 Series and you can test and debug them with the help of the powerful emulator.
Expression Blend 4 for Windows Phone allows you to reduce your development times when you need to create complex UIs. If you want to learn as fast as possible, you can work with Expression Blend in combination with Visual Studio 2010. There are many new namespaces and you have to learn many new classes to interact with the phone capabilities. However, you still have to work with a combination of XAML and C#. Silverlight for Windows Phone 7 Series provides an excellent opportunity to create mobile, rich, and interactive user interfaces that interact with services on the cloud.