Eddie Trimarchi, one of Australia's best astrophotographers, has kindly written a how-to guide for the use of Flats and Darks in digital imaging.
You can find the article at the IceInSpace
How-To page, or by clicking on the following link:
Digital Imaging - Flats and Darks Explained!
Many thanks to Eddie for contributing such a great article, and sharing his knowledge so that others can benefit and produce better images as a result.
You can see Eddie's great astrophotography at his website:
The Tin Shed Observatory