Trolltech Qtopia was the first framework that enabled GNU/Linux to run on embedded systems, like Sharp Zaurus, that did great by end of this decade.
While it did great, being based on Trolltech Qt, it was version 2 and while Qt improved a lot in version 3, Qtopia was never updated and no free version was available.
Now Qt is in its 4th generation and have great improvements, like painting system (Arthur, similar to Cairo) and text engine (Scribe, similar to Pango). They have a really easy and intuitive API, while being very optimized, Arthur supporting even OpenGL-ES. And the big news was that Qtopia was upgraded to cope with Qt4, making things interesting again that Gtk was doing its first inroads on embedded systems.
The bad news so far was that Qtopia4 was closed source, but since Trolltech announced their Greenphone people were asking Trolltech to release it. Being a good Open Source citizen, they did a wonderful announcement releasing Qtopia 4.2 as GPL.
Great work Trolltech! Now I just hope someone will have it running on Nokia 770, bringing some competition to Maemo, at least some speed comparisons.