MIT OpenCourseWare is a free publication of MIT course materials that reflects almost all the undergraduate and graduate subjects taught at MIT.
Indiana University's eTexts Initiative exploring new models to lower the cost of educational resources and take advantage of new opportunities to enhance student engagement and learning.
Flat World Knowlege Sustainable business model that provides free copies of textbooks online, lower costs print versions, pays authors and allows remixing and customization by educators.
Open Course Ware Consortium -- collaboration of higher education institutions from around the world creating a broad and deep body of open educational content using a shared model.
Student PIRGs Open Textbooks -- helps users find high-quality college texts offered online under a license that allows free digital access and low-cost print options.