Press SHIFT + Command Key (Apple key) + the number 3.
This will take a picture of BOTH screens of your system.

OR

To take a picture of just a select portion of the screen:
Press 4 instead of 3 in the steps above, and you will either get a little cross which will then allow you to lasso a portion of either screen (in this case lasso just your keyboard), or you will get a little circle type of icon. If you get the circle-icon, just use it to click on your keyboard. Whether you get the little cross or the circle depends on the version of your Operating System.

In all of these instances you will create a PICT file that will be named Picture 1, and will be found by opening your internal hard drive. Subsequent screen snaps will be be named Picture 2, Picture 3 and so on.

Take a snapshot of your Top Level in one of the following two ways:

Taking a picture of the TOP level of your keyboard is quite a bit trickier since you have to press the SHIFT key to take the picture. However, Avid and Final Cut Pro Guru (and now esteemed Hershleder.com contributor) Scott Barbour has solved a long-standing frustration. Here's his solution:

1 - Place your cursor on the Title Bar (top portion) of your keyboard
2 - Hold down the mouse button (this is the crucial step)
3 - Press SHIFT + Command Key (Apple key) + 3 or 4 as mentioned above

It's a two handed job . . . or maybe you could hold the mouse button down with your foot!!
If for any reason this method does not work for you, I have included the other methods I know of listed below:

If you are quick enough, and kind of stab the three keys quickly, you can get a picture of the Top Level of the keyboard. It IS possible (though frustrating). You'll get a feel for it after about six times or so.

Another way is to go to Shareware.Com and get a great, easy to use little program called SNAPZ. It costs $20, but is useful for many things including capturing the ever elusive top level of your keyboard. If anyone knows some other methods of taking screen snapshots, please pass them along.

Happy snapping!