I have a Sony Vaio vgn-fz240e laptop. Since Ubuntu gusty onward, including a bunch of distros, changing the screen brightness never worked. This caused my battery to drain extremly fast.
Surprisingly, I installed fedora 10 today and unpluged it to move somewhere else, realizing later that the brightness actually dims for the first time ever!! This is great news :]
Hopefully it will work with Ubuntu soon (jaunty). I'm so excited that the fedora devs got it working well. Great job :]