Personally I highly prefer QT to wxWidgets but that is just me. QT can be hard to take in at first because of how big it is, and everything that it can do. Though once you get past learning what everything is and does it is much more powerful then wxWidget.
The con: You need to know C++ was sort of sarcastic. I just meant that some prior knowledge is required.
Regarding your questions about forms: Try Qt Creator. The creator will allow you to play around with forms like you would in Visual Basic. Then, you go to a "slot" and it creates a function header for you and brings you to the "fill in here" implementation part. It couldn't be easier once you know your way around Qt Creator.
In Qt Creator, they also give you the option of trying a few tutorials. Try the widget-based-application tutorial.
@Stewbond
In that case I owe you two apologies. 1) For not catching the sarcasm in the remark. 2) For quoting you as Stewbound instead of Stewbond even though I just corrected it. I get a little frustrated when people mess up my user name so I try to not mess up others user names.
I just had to use Qt for a small game for school. It took me about a month (long after the project was due) to understand how to use the event-driven things, but even for someone with absolutely no GUI/visual experience, it was rather simple to pick up.
It was Qt 1 and Norwegian, when I first did hear of it. We had SGI IRIX as main platform back then. It has taken more effort to port Qt 1->3->4 than it took to port IRIX->{Linux,Win32,OSX}. Oh well, there was no standard C++ either.