MERLOT (Multimedia Educational Resource for Learning and Online Teaching)
Provides online materials from multiple disciplines yet focused at the higher education level.
Perseus Digital Library
Digital materials focused on the humanities, such as Classics, English Renaissance, as well as Bolles Collection with London atlas.
National Science Digital Library
A centralized place to search for science, math, and technology resources.
Open and freely available courses modules in multiple disciplines though strongest in Music and Digital Signal Processing
H-Net Humanities and Social Sciences Online
A centralized place that hosts numerous specialized discussion boards for arts, humanities, and social science scholarship.
Arthur W. Chickering and Steven C. Ehrmann, "Implementing the Seven Principles: Technology as Lever," AAHE Bulletin, October 1996, pp. 3–6.
John D. Bransford, Ann L. Brown, and Rodney R. Cocking, Eds., "Technology to Support Learning", Chapter 9 from How People Learn: Brain, Mind, Experience, and School, Committee on Developments in the Science of Learning, National Research Council, 1999, pp. 194-220.