The GIMP (GNU Image Manipulation Program)

The GIMP is a great free graphics editing program. Use this instead of paying hundreds of dollars for a commercial program like Photoshop or Fireworks. It can be used to create professional quality graphics. The film version of GIMP was used in the creation of the movie Scooby Doo.

The GIMP -- GNU Image Manipulation Program.
GIMP Tutorials -- Tutorials on how to use the GIMP.
Grokking the GIMP -- a book about how to use the GIMP which you can purchase, or download for free.

Royalty Free Stock Photos and Clip Art

Stock.xchng -- Free photos for your needs.
iStockPhoto.com -- A large selection of royalty-free photos for your web sites starting at $1 per photo.
Open Clip Art -- "This project aims to create an archive of user contributed clip art that can be freely used."

Photoshop

Tutorials on how to use Photoshop.

Tips for beginners from elated.com
More beginner tutorials from elated.com
Photoshop101.com
AbsoluteCross.com Tutorials
Photoshop Road Map Tutorials
Planet Photoshop Tutorials
McCannas Photoshop Tutorials
Phong Photoshop Tutorials
Pixel2Life Photoshop Tutorials
Photoshop Tutorials from Adobe
Making glassy bars in Photoshop
Photoshop Support Tutorials
Hands-on Photoshop Tutorials
GUIStuff.com -- a few tutorials (registration required).
Devshed.com -- This ised to be a site called
Sticky Sauce but it changed to Devshed.com. You can still find the Photoshop
tutorials in the archives if you type 'photoshop' into the 'igrep' search bar.
Photoshop Roadmap Tutorials

Fireworks

Another great program for preparing images for the web.

Tutorials from Macromedia