Today Microsoft announced XNA Game Studio 4.0. New to XNA Game Studio is support for Windows Phone 7 Series, the Xbox Live APIs, access to the WAVE devices, and the notion of a managed and non-managed developer.
Where Microsoft technologies are concerned I'm used to managed being almost synonymous with developers targetting the .Net CLR. It means something different in this context. A managed developer is one with which Microsoft has partnered. Developers with Managed status have access to the Xbox Live APIs. non-managed developers would include hobiest and any one else not partnered with Microsoft.