The artist’s guide to GIMP effects

The artist’s guide to GIMP effects : creative techniques for photographers, artists, and designers/ Michael J. Hammel, No Starch Press, 2007

The Gimp has needed this book for years. Gimp has a quirky GUI that can be learned with a bit of patience. Now, with this book, an artistically inclined person can jump in and easily learn how to use Gimp.

Adobe Photoshop elements 6 maximum performance

Adobe Photoshop elements 6 maximum performance : unleash the hidden performance of elements / Mark Galer, Focal Press, 2008

Here is a great guide to Photoshop Elements, and claims that you can get the same professional quality results as if you used the full version of Photoshop. It has a DVD containing supporting images and movies.