You could also take a look at WxWidgets:
http://www.wxwidgets.org/[
^]
A tutorial on building a good gui, and a tutorial on a particular toolkit/library usually doesn't have much in common.
If you want to build a good gui, you need to investigate the usage scenario. A good gui for a casual user is usually a really bad gui for a power user - and vice versa :)
Regards
Espen Harlinn