I think Herb Sutter talked a fair bit about this at the Build and C++ and Beyond conferences last year.
The gist of it (IIRC) is that while managed code may be better for developer productivity, C++ continues to win when it comes to performance/size. Microsoft's trying to take a "best of both worlds" approach: promoting C++11 as a first-class language on Windows (WinRT), and making interop between managed and C++ code easier (C++/CX, formerly C++/CLI, formerly Managed C++).
The gist of it (IIRC) is that while managed code may be better for developer productivity, C++ continues to win when it comes to performance/size. Microsoft's trying to take a "best of both worlds" approach: promoting C++11 as a first-class language on Windows (WinRT), and making interop between managed and C++ code easier (C++/CX, formerly C++/CLI, formerly Managed C++).