D-Lib Magazine: the magazine of digital library research. 

Digital Scriptorium is a growing image database of medieval and renaissance manuscripts that unites scattered resources from many institutions into an international tool for teaching and scholarly research. It bridges the gap between a diverse user community and the limited resources of libraries by means of sample imaging and extensive rather than intensive cataloguing. 

The Library of Congress has made digitized versions of collection materials available online since 1994, concentrating on its most rare collections and those unavailable anywhere else. The following services are your gateway to a growing treasury of digitized photographs, manuscripts, maps, sound recordings, motion pictures, and books, as well as "born digital" materials such as Web sites. In addition, the Library maintains and promotes the use of digital library standards and provides online research and reference services. 

The University of Florida Digital Collections (UFDC) hosts more than 300 outstanding digital collections, containing over 8 million pages of unique manuscripts and letters, antique maps, rare children's literature books, theses and dissertations, newspapers, historic photographs, oral histories, and more. The University of Florida Digital Collections (UFDC) enables users to find unique and rare digitized materials held at the University of Florida and partner institutions.

NYPL Digital Gallery provides free and open access to over 800,000 images digitized from the The New York Public Library's vast collections, including illuminated manuscripts, historical maps, vintage posters, rare prints, photographs and more.