Microsoft AppHub, now open to all members
The new Microsoft AppHub is a subscription based website created by Microsoft and for developers who create marketable apps for Microsoft Windows Phone 7 and Xbox LIVE. The App Hub will also offer many free tools that will include Visual Studio 2010 Express, a Windows Phone Emulator, XNA Game Studio 4.0, Microsoft Expression Blend for Windows Phone, Silverlight, .NET Framework 4 with tons of sample code and a community support. Microsoft is also planning to add several educational resources geared towards helping develop apps and games for Windows Phone 7 and Xbox 360.
An all new Microsoft Developers online resource