system power profile

[Chris Collins]

Hello

I have been running 5.1-stable on my Vaio 505GL for about a week now and
things are working great. I am still trying to figure out a few things that
hopefully some of you can help me with.

I have noticed that when my laptop boots is selects a system power profile
'economy' and I have also noticed a few times it has changed to profile
'performance'.  My question is how can I define what these profiles are and
how can I select them manually myself. 

The second thing that I cannot seem to figure out is how to change the screen
brightness. Can somebody point me in the right direction, I am not sure where
to even begin. 

Thanks
Chris