MIT OpenCourseWare

MIT opencourseware is the new intitiative from MIT, opening up the vast resources that MIT have to everyone who wants to make use of their information and lecture content.
The site is easy to use and has an enormous wealth of courses and info. I cannot recommend it enough.
It appears to be part of a conserted effort to embrace the open source aspects of information sharing on the web, and I think seeks to help set a standard, at least amongst educational institutions, to adhere to similar open source principles.