So I need some advice here. I've never done much GUI programming so I'm at a bit of a loss about what to use to create a GUI for a map editor I'm making. So I was hoping to get some useful suggestions about what I can/should use and where I can get info on it. I'm using C++ and VS Express, and I've been trying to find tutorials on using the win32 API, and I've found bits and pieces but nothing that made much sense to me. I'm also drowning in a sea of abbreviations (do I need to use COM, ATL, .NET, WTF?) Really, I'm pretty lost and hoping someone can throw me a lifeline. Any suggestions greatly appreciated.

If you want to write a GUI that only runs on Windows, I definitely recommend using C# over C++. It's *very* easy to build GUI applications using Microsoft's VS for C#.

Whereas there are materials out there for C++ win32 programming, I'd argue there are better tools for the job :) If for some reason it needs to be C++, I'd advise having a look at either GTK (and use Glade to build the UI) or at QT and QT designer.

(Of course, for C++ you would use the GTKmm library and Glademm!)

I've got nothing to add to the previous posts but one thing:

I think you can use everything but C++ to construct a UI. This statement isn't language based but framework based. Java AWT/Swing, the .NET framework, etc are professionally build frameworks that exist for one purpose: make your life easier.
After all, you want to make a level editor, not a window manager or event manager.

So make your life easy and use a framework.