This afternoon I discovered an excellent collection of links to military and military-related internet resources on the website for the library at the Joint Forces Staff College in Norfolk, Virginia. The Index to Internet Sites for JFSC Researchers lists sites by subject. Another good source of military and defense information is the GPO Access Browse Topics site, a partnership with the library at Oklahoma State University. Topics include military history, defense and security and homeland security.
For scientific and technical information from the Department of Defense, search DTIC's Scientific and Technical Information Network. The multisearch feature lets you search across an array of government databases.