Cancel Downloads from the Mac App Store
While clarifying the instructions on how to re-download Mac OS X Lion from the App Store I discovered a neat little trick; you can cancel downloads.
Hold down the Option key from the “Purchases” menu in the Mac App Store, this causes the “Pause” button to turn into “Cancel”
If you click that “Cancel” button you will get a warning dialog box asking to confirm that is what you wanted to do, and reminding you that can re-download the app again for free at any time.
The ability to re-download purchases from the Mac App Store is part of the personal use license for OS X Lion and other apps offered through the App Store as well, as long as you are downloading them on your personally authorized Macs using the same Apple ID.