Math/Science

• SOS Math - tutorials
• Math world - definitions
• How Stuff Works
• How Things Work

Search/Reference

• Google.com
• labs.google.com - new projects
• dictionary.com - also translations
• whatis.com - tech glossary
• Webreference

News

• news.google.com
• arstechnica - tech news
• slashdot - tech news, discussion

Computing & Web Design

• homenethelp.com - networking tutorials
• Yale Style Manual
• Webpage Design Flaws

Other

• Princeton Online Lectures - videotaped lectures
• Amateur Scientist