You can choose between auto-scan or manual scan. With auto-scan you can specifiy a particular folder to scan, or simply scan your whole hard drive(s). Quick Icon Grabber will then locate these icons and save them in a variety of formats (.ico, .bmp. jpg, .gif).
In manual mode you manually scan a folder, select the icons you want, one at a time, and save in one of the above-mentioned formats.
Most graphics packages don't allow you to save images as icons, so you won't be able to to alter your current icons and use them on your system. You can, however, grab icons from your system and edit them for use elsewhere.