Free images is a high quality resource of digital stock photographic images for use by all.
All images are free to use on websites and printed materials.
Netscape Background Sampler
As the title suggests a "sampler" of backgrounds.
Media Links Free Backgrounds & Textures
WOW ... Huge collection of free backgrounds and textures by several great artists.
ER Backgrounds & Textures
Over 375 backgrounds and textures indexed in 12 easy to use different groups. A Texture View has been added to the Background section to allow you to evaluate what the texture would look like on a page.
Art for the web
Offers a nice selection of backgrounds and other graphics such as complete page templates. A bit slow to load but worth the wait.