According to the Open Courseware Consortium, "An OpenCourseWare (OCW) is a free and open digital publication of high quality college and university‐level educational materials. These materials are organized as courses, and often include course planning materials and evaluation tools as well as thematic content. OpenCourseWare are free and openly licensed, accessible to anyone, anytime via the internet".
The concept of OpenCourseWare was initiated in 1999 when Massachusetts Institute of Technology (MIT) Faculty examined the most effective ways to use the internet to advance the MIT mission. See http://ocw.mit.edu/about/our-history/.
CSU Affordable Learning Solutions
Scroll down the page to find a list of Open Courseware (OCW) providers.
Open Courseware Consortium is a rich source of courses
Carnegie Mellon courses stand out because of their collaboration with cognitive scientists on their campus
with their Open Learning Initiative. http://oli.web.cmu.edu/openlearning/index.php
Monterey Institute's National Repository of Online Courses
MIT's OpenCourseWare project has been one of the biggest inspirations for the OER movement, but many of
their course pages are just outlines. More interesting are their courses with "substantial" audio-visual content.
UC Berkeley http://webcast.berkeley.edu/ online video and audio for a variety of courses
Oxford http://podcasts.ox.ac.uk/ also offer free but limited video course broadcasts.
The Internet Archive provides an archive for free/open courses. http://www.archive.org/details/education
Open University Coming from across the Atlantic, the Open University gives us access to course materials
via its Learning Space http://openlearn.open.ac.uk/