Links to websites with Photoshop resources and materials:
Adobe Marketplace and Exchange – official Adobe site for add-ons, join for free
Retouching Vimeo Group – useful collection of tutorial videos (including some of the ones on this site)
QBrushes – free Photoshop brushes
Texture Lovers – high quality free textures
Media Militia – collections of free shapes, brushes, graphics and textures
Tutorial Sites:
Russell Brown Tips – the great Photoshop eccentric is endlessly informative . . .and entertaining!