UPDATED 16th March 2006: Capture a Screencast with a Mac — tutorial on how to organise yourself before doing a screencast by Miraz Jordan.
Mac OS X comes with its own screen grabbing tool called Grab and it is fairly comprehensive but I needed something more powerful as I intend using this a whole lot more. On doing some quick searches I landed up here at Pure-mac with 26 applications to choose from. Holy Moly! Jeremy helped me pick the best one and I tell you this is one kick ass screen capture software. Wow!
Once you have installed the program hit Shift + apple + 3 Tell me what you think! Sick! 
Er… in OS X also has a built in system for screen captures.
If u hit ‘command’ + ’shift’ + ‘3′ u get a full screen grab, and if u hit ‘command’ + ’shift’ + ‘4′ u get a small selection tool that you can select any part of the screen with.
Images are automatically saved on the desktop as a .pdf and you can then edit them in photoshop or export them to .tiff or .jpg via Preview.
Why the need for an additional app?
It sure does but is no where near what SnapzProx does. You should really try it. Grab is not bad but isnt just half as powerful.
SnapNDrag should do the trick and it’s free!
http://www.yellowmug.com/snapndrag
Thats exactly my point, many softwares free or otherwise would ‘do’ the job but only one would the best possible way!
And even in 2007!! As this link will tell you.