Though the idea of OpenCourseWare originated in Germany in 1999, it was MIT's program that began in 2002 that ushered in OCW as we know it. It is entirely free and the material offered is of the highest quality. MIT's purpose in creating OCW was to "enhance human learning worldwide by the availability of a web of knowledge."
You can search a variety of topics, from antiques to test prep in this site!
iTunesU is also a great source of free educational materials that you can put right on your iPod or mp3 player! Convenient AND enlightening!
Source: RCPL blog