I got it on my new laptop Sony VGN-NR38S, after looking all over the internet for info, i came across with this tread here, so for me and for now you have to run this on terminal.Using Ubuntu 9.04 in this laptop.
First make sure that you have this installed in your system,
look in synaptic package manager
or type in terminal: smartdimmer
if installed in terminal, you will see this
sudo apt-get install smartdimmer
you can copy and past it in terminal.
Using the terminal to decrease brightness,
open terminal if is closed and type: smartdimmer
this command will bring options like this
will show the level of the brigtness
this will increase or decrease brigtness
will increase 1level and
the command: smartdimmer -d
will decrease 1livel