Remember: they said Java would be the death of C and C++...
I'm still programming primarily in C++, hrm...
I know MS is still improving it's C++ support. There is no possible way that MS is going to drop C and C++ development. Once C# gets settled, that's one thing -- if it's fast, I might use it. But for right now, C/C++ is the way to go a lot of the time (admittedly, I also know VB should be used sometimes...).
Considering MS is making sure .NET is accessible to C/C++, you should be fine.
I've looked only briefly at C#, but from what I've seen it has a lot in common with C++. As long as you think more than you program, you should be fine. 🙂
And I'm sure we'll see some "C# for C/C++ Programmers" coming soon. 🙂
Andrew