Academic Earth | http://www.academicearth.org
Free online lectures from universities such as Berkeley, UCLA, Harvard, MIT, Princeton, Stanford and Yale. Subjects include: astronomy, earth sciences, computer science, economics, English, history, mathematics, medicine, and social sciences.
CITE | http://thecite.blogspot.com
A blog on course materials, innovation, and technology in education.
edX | https://www.edx.org/
Freely available online course lectures from prominent universities, including UC Berkeley and MIT, among others.
Flat World Knowledge | http://www.flatworldknowledge.com
Provides a new approach to college textbooks offering rigorously reviewed textbooks online free of cost to students.
Free Technology Academy | http://ftacademy.org
FTA is a virtual campus with course modules that can be followed entirely online. Learners enrolled in the FTA will be guided by professional teaching staff from the participating universities around the world.
Internet Archive: OERs | http://www.archive.org/details/education
Provided by the Internet Archive library, hundreds of free courses, lectures, and supplemental materials from universities in the United States and China. Many of these lectures are available for download.
Khan Academy | http://www.khanacademy.org
An online collection of thousands of video tutorials on subjects such as mathematics, history, finance, physics, chemistry, biology, astronomy, economics, and art history.
Mendeley | http://www.mendeley.com
Organize, share, and discover research papers. Explore research trends and connect to other academics in your discipline.
Notre Dame Open Courseware | http://ocw.nd.edu
An open access portal to University of Notre Dame material used in courses.
Open Courseware Consortium | http://www.ocwconsortium.org
Free and open digital publication of high quality educational materials, organized as courses, from more than 200 higher education institutions and organizations from around the world.
Open Yale | http://oyc.yale.edu
A freely accessible, online collection of courseware from Yale University. Lectures and course material available through YouTube and iTunes; no registration required.
OER Blogs | http://oerblogs.org
OER Blogs is attempting to unite the world of Open Educational Resources.
Pimsleur Language Learning | http://www.pimsleurapproach.com/resources/
Great resource for learning Spanish, French, Arabic, German, and other languages.
WikiBooks | http://en.wikibooks.org/wiki/Main_Page
An online wiki-based collection of over two thousand open-content textbooks. Fully editable, published under the Creative Commons Attribution-Share Alike License.
Wikipedia | https://en.wikipedia.org
This well-know encyclopedia is both created collaboratively and open source. Available in multiple languages.
Wikiversity | http://en.wikiversity.org/wiki/Portal:Tertiary_Education
Another wiki-based resource containing thousands of open educational resources on the university level.
Wolfram|Alpha | http://www.wolframalpha.com
A free online computational knowledge engine. Highly useful for complex queries, high level mathematical computation, and statistical comparisons.
World Digital Library | http://www.wdl.org/en/
Primary materials from countries and cultures around the world, made available online free of charge.
Bookstore and cafe, South Korea. Photo by Nathan Cooke. Flickr Commons.