Consult this list to find classes and training opportunities in our community:
Official Mac news and information page.
Tutorials geared to helping GIMP users who need to make a quick change to an image for some project, but don't want to learn about computer graphics right now in order to get the image changed.
Tutorials on how to use GIMP.
Official GIMP forum site with tutorials for using GIMP, including video tutorials.
Grokking the GIMP
E-book for learning advanced digital image editing techniques using the GNU Image Manipulation Program, the GIMP.
This tutorial shows how you can do vignette effects using a feature of GIMP called QuickMask.
The GIMP 2.6-User Manual
Online guide to GIMP software.
The GIMP 2.8-User Manual
Online guide to the latest GIMP software