The Internet Archive, a 501(c)(3) non-profit, is building a digital library of Internet sites and other cultural artifacts in digital form. Like a paper library, we provide free access to researchers, historians, scholars, and the general public.
There are a ton of older books, older video clips, legal audio stuff, and more here.
Most importantly to those of us who have lived on the net for a while....It is the new home of the Wayback Machine!
For those fo you who do not know, the Wayback machine is an archive of the entire internet. Browse through over 150 billion web pages archived from 1996 to a few months ago. To start surfing the Wayback, type in the web address of a site or page where you would like to start, and press enter. Then select from the archived dates available. The resulting pages point to other archived pages at as close a date as possible. Keyword searching is not currently supported. But who cares. It is great.