[wheels]

Qt's a pretty general toolkit for C++ applications – a pretty huge chunk of it has nothing to do with GUI programming (and what, for instance, the KDE desktop and associated tools are built on):

http://doc.qt.nokia.com/4.6/classes.html

It was fairly recent that Nokia bought them; before that Trolltech was an independant company.

[ovi256]

It's a kickass toolkit (and my toolkit of choice) for cross-platform desktop apps. Just keep in mind that it's GPL licensed for free apps and that the commercial license is expensive for a one-man shop.

[noste]

Qt is also available under LGPL 2.1. See http://qt.nokia.com/products/licensing for details.