Below are links to various Photoshop Tutorials
Photoshop - FreeTutorials.com
Photoshop - AndyArt
Photoshop - Creating Textures
Dr. Ozone Photoshop - Tutorials
Absolute Cross - Tutorials
3dPallete - Creating Seamless Textures
3dPallete - Photoshop Basics
EyeBall-Design - Great Photoshop Tutorials
PluginHead - Photoshop Plugins
Phong.com - Photoshop Tutorials