That depends on your definition of free. According to our definition it is free, since:
The Qt libraries and source code are available for free and are readily available on many FTP site.
You can run application written using Qt for free. No run time charges apply.
You can develop application with Qt for free as long as you make the source code of your applications written in Qt readily available. Note -- you can even sell your application, however you must make its source code readily available if you wish to avoid buying a license for Qt.
You can distribute Qt as well as application using Qt in any form -- be it on FTP sites or CDs. In particular all Linux distribution may press a copy of Qt and its source on their CD's free of charge.
As KDE was, and is, intended to be a noncommercial desktop environment for the X Window system, Qt fits our purposes.
Qt is constantly developed by Troll Tech's dedicated, professional staff. Troll Tech devotes all of its resources to improve Qt on a daily basis. Due to this fact Qt continues to develop at a rate unmatched by any L/GPL'ed toolkit, providing us with the best toolkit available under Unix and providing possible commercial developers for KDE with the quality and support they need.
Troll Tech AS has announced that the Free Edition of Qt, its popular Graphical User Interface toolkit, will be released under an Open Source license. With the new license, programmers will be able to distribute and share any modifications they make to the Qt Free Edition. A draft version of the new license text, dubbed the QPL, is available at http://www.troll.no/qpl/. It will be first applied to the next major release of the Qt Free Edition; version 2.0.