Dim Monitor

Is it possible to dim a secondary monitor connected to your laptop?

I have a gateway 7322GZ laptop and I have connected a secondary monitor to it. The screen is very bright and the setting is at it's lowest for dimming, is there any way to dim it even more?

I don't know of any way to adjust the brightness other than on the actual monitor, but maybe make your other monitor brighter to even it out?

Dim Monitor Screen - Xcalib - Ubuntu 10.04