Open Science Directory - FREE contains just over 13,000 free journals, including the Directory of Open Access Journals, and peer-reviewed journals covered by High Wire Press (Stanford University - the largest archive of of free full-text articles in science and medicine). Easy identification of issues and available years.
Mag Portal FREE Updated every few days. Separate section for Computer Science and Electronics. Searchable, easy to browse directory of magazine articles on science and technology available online. Topics include audio, desktop, laptop, linux, Macintosh, Mircosoft Windows Network; PDA's, telecom and handheld devices; peripherals, servers and super computers, software use, reviews & news; television, DVD & equipment; Unix; video and digital photography.
How Stuff Works - "explains simply, with excellent diagrams or pictures, how many common appliances, machines, and technologies work."
Ten Cool Sites in Science - from the Exploratorium. Every month's site puts up listings of new sites that have been reviewed. Previous choices are available in a subject organized archive. There is a separate archive for Math, mostly for teachers K-HS.
World of Science - Eric Weisstein's comprehensive and interactive, searchable encyclopedia of astronomy, scientific biography, chemistry and physics, and mathematics.
Selected Internet Resources in Science and Technology - from the Library of Congress Research Centers; links to government agency sites as well as outside links for almost 40 different subject areas in the sciences. Great first stop on your research journey.
ACM Digital Library - Summaries and article information [not full text] from the publications of the Association for Computing Machinery, the leading organization in computing.
CNET - Provides technology information for buyers, users, and sellers
Computing Gateway - free access to high quality sites, chosen by subject specialists.
Internet Archive - Wayback Machine can look at a Web site and track how it has evolved [see how events like 9-11 were recorded digitally] Now contains over 85 billion archived Web pages.
Webopedia - Online dictionary and search engine for computers and Internet technology
What is - definitions for thousands of the most current IT words
Yahoo Computer Science Very popular site on the Yahoo Directory which is a good jumping off point. Sites are evaluated and you can restrict your search to just computer science (or math) categories instead of the entire Web.