Good place to read up on the latest in science
Breakthrough Propulsion Physics Program
MathPad is a general purpose graphing scientific calculator for the Mac
Image and ImageJ are excellent, free image processing programs
is a free PCB layout and routing program
The Last Word
Science Questions and answers
John Cramer's "The Alternate View"
Great essays about cutting edge science
David Deutsch's Home Page
Quantum computing and Multiverses...(multiple universes)
Pete Stark's page
Pete's 6802 articles in Kilobaud and other work taught me a great deal.