http://www.pdphoto.org/
PDPhoto.org is a repository for public domain photos. Use the photos for
anything, including commercial uses, other websites, school projects, articles,
ads, whatever. Public domain means the photo is not protected by copyright and
may be freely used by everyone. Unless something is clearly marked as being
something other than public domain, you can assume it is free to use.

http://www.freegraphicsworld.com/
 - buttons, bullets, banners, backgrounds, templates, layouts
You can use them for anything (even commercially). All of our graphics are
licensed under the Creative Commons Attribution 3.0 license, so they are
entirely free for personal and commercial as long as you credit us in some way.