Qt, even though it’s been available for noncommercial use for quite awhile on Linux as GPL, is completely relicencing to LGPL–which means it’s “Free as in Beer and Freedom Free” for all the Stallman-esque obsessives out there. Not that anyone paid for Qt, really. Use for KDE, then for Linux, has been non-commercial for ages, but Nokia’s ownership and oversight of Trolltech means profit for the toolkit is unimportant. The more Qt, the better. One of their first moves was a quick open-sourcing of Qt for Windows.
So another set of kudos for Nokia! If you’ve been holding out on using Qt for whatever, don’t. If you’ve been using Gnome, I’m sorry. If you want to rediscover goodness in programming, do so. It’s LGPL/GPL goodness all around.
Also, since Qt is being actively ported to everything, try out QtCreator. It’s goodness in a cup and runs on both Windows and Linux. Don’t ask me about OS X, since I no usey teh losey. I kid, I kid. But I think it’s available for OS X, too. The whole thing is beta, but I’ve heard good things.
Last but not least, KDE 4.2 Beta is out. =)