Info from Steve Teixeira, the Director of Partner Strategy for Microsoft Visual C++,:
MFC continues to be the C++ application framework of choice for many developers because the breath and depth of support that MFC provides for the Microsoft platforms remains unmatched by other frameworks. Visual Studio 2005 makes it possible for the C++ developer to leverage existing C++ code, the strengths of MFC, and the advantages of .NET, all within a single application.
Looking beyond Visual Studio 2005, C++ developers should expect deepened integration between MFC and the .NET framework. After the release of Windows Longhorn, Microsoft intends to add MFC support for key Longhorn APIs and features. Microsoft also intends to support the Avalon user interface framework in MFC, providing MFC developers with a bridge to the future of platform user interface design. In essence, as the platform evolves, developers can look forward to seeing MFC updated to leverage the latest managed and native APIs and frameworks.
MFC developers have access to more frameworks than any other type of developer on the platform. As such, MFC developers are free to leverage the best from all worlds as it makes business and technological sense to do so. Microsoft fully expects to support this capability into the foreseeable future.
Detail: http://msdn.microsoft.com/visualc/whidbey/mfc2005/default.aspx