Whether you use a commercial program like Photoshop or CorelDRAW, or an open source alternative like the GIMP, there is a big learning curve between taking your first scribbles and masterfully editing a photo. The tutorial videos shown below include tips for both GIMP and Photoshop, and the techniques can often be translated directly to whatever photo editing software you use. If you don't find what you need here, you can also check out Graphics Champ.