Split Screen on a Mac

So whenever I go to the mall (which is not often), I like to stop by the Apple store and play with the new gadgets.  While I prefer a Mac, I have never been able to easily (yes you can drag the windows and re-shape them) split the screen in half the way you can on a Windows based computer (go here if you don't know how).  Well (and I am getting no $ for saying this), but you can try new software (for a temp fix) or pay $7 to be able to easily snap (as you can on Windows 7) the screens in half on your Mac.  It comes from PC World, so I think you can trust it.