OER are digital resources that are in the public domain or under licensing that permits free use and re-purposing. They can include full courses, course modules, course materials, quizzes, tests, videos, simulations, syllabi, or other materials that support teaching and learning.
MERLOT is a free and open online community with peer reviewed online teaching and learning materials.
MIT OpenCourseWare is a free publication of MIT course materials that reflects almost all the undergraduate and graduate subjects taught at MIT.
NROC is a library of high-quality online course content for students and faculty in higher education, high school and Advanced Placement.
ISKME created OER Commons, publicly launched in February 2007, to provide support for and build a knowledge base around the use and reuse of open educational resources (OER). As a network for teaching and learning materials, the web site offers engagement with resources in the form of social bookmarking, tagging, rating, and reviewing.