This is good news. KDE is ported to Windows/Mac and the users of those operating systems will become more familiar with it.
Although some people think open source programmers should not waste their time on proprietary OSes such as Windows I still think this is a good thing.
The move was eased by using CMake build system. Also, it helped that Trolltech made Qt libraries GPL for non commercial projects on Windows/Mac.
Read about it here and at the KDE website Windows section.