The Federation of American Scientists http://www.fas.org/index.html is a comprehensive site dealing with defence planning and technology.

The National Security Archive of George Washington University http://www.gwu.edu/~nsarchiv/ is an online repository of documents and commentary pertaining to strategic issues.

Global Security http://www.globalsecurity.org/ is exceptionally strong on weapons and other military systems.

Air University Bibliographies http://www.au.af.mil/au/aul/bib97.htm offers hundreds of specialized bibliographies on topics relevant to the study of war, strategy, and international politics.