Mac screen capture FAQ: What are the keystrokes to create screen capture images on Mac OS X?
One of the great things about Mac OS X is that it's pretty easy to create a screen capture. You can capture the entire screen (like using the Print Screen button on a PC), select a region to capture, or capture an application window without needing any third-party tools. The only hard part about this is trying to remember the magic Mac screen capture keystrokes.
Mac screen capture - Entire screen: To take a picture of the entire screen press [Command][Shift] (the number 3, not the [F3] key), and the screen capture will be saved on your desktop. The first picture is named "Picture 1.png", and the number is incremented as you take more pictures.
Portion of the screen: To select a portion of the screen you want to capture, press [Command][Shift], and you'll see a small crosshair selector on your screen. Just click-and-drag the section of the screen you want to capture, and again your image will be saved to your desktop.
Mac window capture: To easily capture a window from an application, again press [Command][Shift], but when you see the crosshair cursor press the [spacebar]. This turns the crosshair cursor into a camera cursor, and the camera lets you take a snapshot of any window you select.
Knowing these Mac screen capture keystrokes is great stuff, but if you want even more power, I just updated this article on my favorite Mac OS X screen capture application/utility. Although it's not free, I did buy it, and I use it all the time now, and can't even come close to remembering these Mac screen capture keystrokes without searching for this article myself, lol.