Today at the MIX 2010 conference in Las Vegas Microsoft revealed how developers can create apps for Windows Phone 7 series using the Silverlight 4 and XNA game platform. Microsoft released a free version of the visual studio developer tool called Visual Studio 2010 Express for Windows Phone. The IDE includes everything you need to get started creating Windows Phone 7 Series applications along with a Windows Phone 7 emulator for your PC.
Related:
Microsoft makes test versions of Windows Phone 7 tools available
Silverlight 4 RC, the Windows Phone 7 platform, downloadable today
Microsoft Gives Developers the Hard Sell at MIX10





