Charles Petzold's free .Net Book Zero is a great introduction to .Net and C# for the C/C++ programmer ... if you're a Windows programmer who's been curious about C# but haven't known where to start, this is where.
Part of a book by Charles Petzold on programming Windows apps with WPF -- includes a link to all the code samples -- which are really great as a learning tool even if you don't have the book.