Sources of good, free icons/images for applications & web apps with permissive license? [closed]

Question

I'm interested in finding good icons/images that can be used in both 'free' and proprietary programs.

Please include a description of any license restrictions associated with the source of the icons you suggest.

Answer 1

I use two search engines:

IconFinder and IconLook.

If you can't find what you want, this blog post has a list of great resources.