The latest Mac operating system, Mountain Lion, comes with some great tools for capturing what’s on your screen. There are a few keyboard shortcuts that allow you to capture the entire screen, portions of the screen, or entire windows depending on your need. The Command, Shift, and 4 keys when held down together at the same time is one of my favorites. It turns your cursor into crosshairs. You can then drag these crosshairs in a rectangular shape around anything that you want a picture of, and you will hear a camera sound when you let go saving the image as a .png file to your desktop. For more keyboard shortcuts ask the pros at Apple; http://www.apple.com/findouthow/mac/#capturescreen
The other great feature is the video capture features that come with new Macs. QuickTime Player 10 comes with a built in video screen capture service. Just open QuickTime Player (comes with newer Mac devices) and click on File -> New Screen Recording. This gives you options to record with audio or not. Not only does the video capture everything you are doing on the Mac laptop, but it accents your mouse clicks and draws the attention of the viewer to what you are doing.
So now you can take pictures and videos of everything you are doing on your Mac. It’s easy to create tutorials now. Just drag those pictures into documents and create illustrated PDFs, or pull your video screen captures into iMovie to edit them with titles, transitions and voice overs to create professional looking video tutorials.
For the more advanced users you can find some great free, and marginally cheap, apps available in the Mac store that also capture screen recordings with flare. These can then be shared to the web for publishing or to another piece of software to add just the right finishing touches.