LCD flickers when computer not actively in use

I'm not really sure what the problem could be, but since it only occurs when the computer has been sitting idle for a while, my guess would be that it might have something to do with the screen saver or sleep mode. Try changing those settings to off (or just delay them longer) and see if the problem still persists. I'm not really sure if that would be a software issue or a hardware issue, but it seems like a good place to start.

I have the same machine (MacBook 2GHz Core Duo), have had the same problem for years and have never received a clear answer on a fix. Here's a link that should give some insight into how prevalent the complaint is and how it's been handled on apple's discussion boards. http://appledefects.com/?p=235

that sounds like a bad backlight inverter, the inverter generates power to drive the cfl lamps that light the display. when they are faulty, they tend to flicker, and let the screen go dark all together. try lovering the brightness, that might minimize the issue, if it still happens once the brightness is completly off, than it might be a panel failure.