A First Course in Linear Algebra
A number of online textbooks have been created in the past several years, and this course in linear algebra is a nice addition to the existing repertoire of such educational materials. Professor Rob Beezer of the University of Puget Sound created this introductory textbook, and he still maintains the site and provides updates periodically.
Math Gateway of the Mathematical Association of America
Created through a partnership with the National Science Digital Library (NSDL), the Math Gateway was developed by the Mathematical Association of America. The site provides a veritable cornucopia of information for educators and those who are curious about anything from algebra to the history of mathematics. Visitors can start their exploration through the site by using the search engine at the top-left hand corner, or they look at the "Content Highlights" displayed prominently here.
Source: The Internet Scout Project