Windows Phone 7 is the latest OS developed by Microsoft for mobile devices. WP7 is competing in the market with other popular mobile OS like: iOS,Android,Symbian,Meego,Maemo,..etc. But its popularity proves its Usability & Functionality and that people still love windows phone 7 .Windows Phone 7 was designed from scratch a new whole platform not an update to the previous one.
Anyway WP7 uses Silverlight and XNA Game studio as its default technologies so anyone who can use Visual Studio and knows how to create windows forms using C# can create and develop WP7 Applications .
U only need to download the Visual Studio SP1 and the Windows Phone 7 SDK then get ready to enjoy real programming.
VS SP1 Link :
WP7 SDK Link :