Academic Earth is an organization whose mission is to give "everyone on earth access to a world-class education" (Robert Ludlow, Academic Earth Founder/CEO). The site provides video lectures and additional educational materials from several major universities (Berkeley, Harvard, MIT, Princeton, Stanford, UCLA, and Yale) across a variety of subjects - chemistry, engineering, physics, and more. Browse by subject, university, or instructor, or search by keyword. More than 200 instructors now provide over 1,500 lectures, some of which are organized into courses of 4 to 50 lectures each.
Follow a particular instructor or subject by signing up for email alerts or an RSS feed, or by becoming a fan of Academic Earth on Facebook. Find your favorite alert method on the toolbar at the bottom of the site:
and stay up-to-date as new content is added to the site. A good resource for students, those who want to learn the basics about a new field, or those who want to stay in touch with current developments within their field.