I currently own two Samsung netbooks (an N150 Plus and an NF310). Following up on some information from Moley (thanks), I found that most Linux distributions have a lot of trouble with the display brightness control on both of them. The most obvious and severe symptom is that when running on battery power they will sometimes (often) suddenly start to run the display brightness all the way up and down its range continuously. Not nice. A secondary problem, not quite so severe, is that the Fn-key control for display brightness is often erratic, and on some distributions doesn't work at all.
I've been looking into this for several weeks now, trying to find a solution, or at least a reasonable work-around. Now, thankfully, I have found both. First, the solution - Fedora 16! Hooray! With all of the latest updates installed, Fedora does not have either of these problems. The display brightness is normal and stable, and the Fn-key controls work in nice, smooth steps up and down. In fact all of the Fn-key controls work, including sound up/down/mute, touchpad off/on, WiFi off/on and sleep. Very Nice.
Alternatively, if you just can't stand to use Fedora for one reason or another, there is also a work-around for a couple of other distributions. Under openSuSE 12.1, you can go to Power Options / Power Profiles, and disable the "Dim Display" function. That will stop it from going into the brightness-cycling nonsense, which is by far the worst of this problem. Likewise, with Linux Mint Debain 201109 (Gnome), you can go to Power Options and disable Dim Display. For the other two major distributions I have loaded, Ubuntu 11.10 and Linux Mint 12, I have not yet found a work-around, and the brightness-cycling seems to be particularly bad with them.