Bookmark It: Connexions

Connexions, a self-described "environment for collaboratively developing, freely sharing, and rapidly publishing scholarly content on the Web" is a fantastic resource you should definitely bookmark (if you haven't already!). They feature modules of information and course content that help readers understand the material by interacting with it in a non-linear fashion (as opposed to learning from a traditional textbook). One feature that you may be particularly interested in: they offer many free digital textbooks--legally--as part of the module setup.

The New York Times reported that Connexions has more than 850,000 unique users each month. Check 'em out and let me know what you think!