The same powerful and easy to use Visual Studio integrated developer environment (IDE) handles developing Windows Phone 7 phone applications.

The Windows Phone Developer Toolkit is required to develop Windows Phone 7 applications, specifically: Visual Studio 2010 Express for Windows Phone and Expression Blend 4 for Windows Phone. These tools provide the same industry leading development workflow for Windows Phone that was previously only available while creating Silverlight or desktop based applications. The same powerful and easy to use Visual Studio integrated developer environment (IDE) handles design and testing of Windows Phone 7 phone applications. With innovative features such as Behaviors, the Visual State Manager and design time data, Expression Blend 4 for Windows Phone enables you to need to rapidly take your ideas from concept to completion accelerating your delivery of innovative apps on Windows Phone.

The Windows Phone Developer Tools includes the following
1. Visual Studio 2010 Express for Windows Phone
2. Windows Phone Emulator Resources
3. Silverlight 4 Tools For Visual Studio
4. XNA Game Studio 4.0
5. Microsoft Expression Blend for Windows Phone

The license of this software is Freeware, you can free download and free use this phone software.