Gimp is an AWESOME image editing program. Though I'm sure I'm antagonizing a heated debate, Gimp is a sufficient alternative to Photoshop. So far I haven't come across a single feature that Photoshop has, that Gimp can't do, for free.

Here are some of the tasks that I've accomplished by using Gimp:

• Creating Web 2.0 Text Logos
• Overlaying an Image with Text
• Creating a Silhouette from an Image
• Whitening Teeth in a Portrait
• Removing Red-eye from a picture.
• Creating Shapes.
• Creating Flames from Text
• And a whole bunch of other stuff I can't remember.

http://gimp-tutorials.net/ has a lot of really powerful tutorials, as well as the tutorials section on Gimp's own website at: http://www.gimp.org/tutorials/