Trolltech announced that they want to dual license Qt 4 for Windows and thus release it as Free Software under GNU GPL for the first time.
Their press release can confuse people as software under GNU GPL can of course be used commercially like all Free Software.
http://www.trolltech.com/newsroom/announcements/00000192.html
Trolltech to Extend Dual Licensing to Qt for Windows
Qt cross-platform development software will be available under the open source GPL license for open source development and a commercial license for commercial development
Qt for Windows will be available under both a commercial license and the open source GPL license starting with the next major production release of Qt, version 4.0, which is expected in the second quarter of 2005.