If you are still Googling for answers about the lost backlight control on your Samsung NC10 after upgrading to Lucid (Ubuntu 10.04), I have the solution.
First add ppa:voria/ppa to your Software Source list. This will add more software into your Software Centre. The quick way to do it is to open a Terminal. Then paste in the following and press ‘Enter’.
sudo add-apt-repository ppa:voria/ppa
Enter your password when asked for it.
Next go to your Ubuntu Software Centre, under ‘Applications’. Just put Samsung in the search box and you will see ’samsung-backlight driver’, click ‘install’.