Copyright and copyleft/public domain
Canadian Public Doman Registry : http://www.accesscopyright.ca/resources.asp?a=198
Center for the Study of the Public Domain http://www.law.duke.edu/cspd/
Copyright-free photo archive containing the largest community-indexed collection of free, public domain images and photos. http://gimp-savvy.com/PHOTO-ARCHIVE/
Public Domain / Copyright Free Media Provides links to copyright-free and public domain resources http://eduscapes.com/tap/topic98.htm
http://www.law.duke.edu/journals/lcp/indexpd.htm
Public Domain & Open Standards discussion at WIPO: What did Mexico, India, Chile and Australia say http://fromgeneva.blogspot.com/2006/07/public-domain-open-standards.html
Value of the Public Domain http://homepages.law.asu.edu/~dkarjala/OpposingCopyrightExtension/publicdomain.html