putting only monitor to sleep

Is there a way to put only my monitor to sleep by pressing a button, as supposed to having to set it to 1 min, and then changing it during the day. I let my computer to large file transfers and other long task at night, so i need the hard drive on and just the monitor to be black.

I wondered this aswell, however I don't think it is possible.

You could just dull the brightness until it is turned off?

you can set an expose corner to a screen saver and have the screen saver be black...thats all i can think of right now, but im sure there is another way....will post back when i think of something else
-chris