The Khan Academy is a small entity which offers over 1800 free instructional videos covering everything from basic algebra to advanced chemistry, biology, and topical issues like today's banking crisis. 200,000+ students use the site each month, and all videos are licensed under CC BY-NC-SA, with some translated into Spanish, Arabic, Mandarin, Hindi, and more.
Khan Academy has no formal university affiliation; popularised recently (2010) by Bill Gates. Now funded by Google, Gates Foundation.
Its web site is at http://www.khanacademy.org