А откуда такая информация о Qt? У нас в конторе коммерческая версия, но вот выдержка из последнего мэйла от TrollTech:
Dear Qt User/Qt Customer:
Trolltech is pleased to announce that we intend to make Qt 4 for Windows
available under our successful dual licensing business model. This
means that Open Source projects under the GNU GPL license will be able
to target all major operating systems using Qt 4. We plan to release the
Windows Open Source version of Qt at the same time as Qt 4.
What dual licensing means
=========================
Qt's dual licensing model is based on the principle of fair exchange. If
you are using Qt commercially - that is, for creating proprietary
software for sale or use in a commercial setting - you must purchase a
commercial license from Trolltech. Alternatively, if you wish to write
Open Source software you can use the Open Source version of Qt, released
under the GPL. If you use the Open Source version you must release your
application and complete source code under the GPL as well...
http://www.trolltech.com/developer/faqs/duallicense.html