hi, I'm a chinese guy using 4810T with ubuntu 9.04 for several days.
About brightness, I tried the ways of editing /etc/default/acpi-support, /etc/laptop-mode/laptop-mode.conf files for LCD brightness control, but it doesn't work.
After doing some seaches on google, I got this method now well working for me
if you don't have xbacklight, just:
$ xrandr --output LVDS --set BACKLIGHT_CONTROL native
sudo apt-get install xbacklight
now change the value you want, and enjoy!
Can define some hot-key in Compiz and bind them with custom sh files in ~/bin.
I have my quetions about multi-touch and power_saving, If you have any good suggestion on them, please tell me.