How Stuff Works is one of those pages that restores my faith in the Internet. How Stuff Works' is a collection of articles that explain the science, technology and engineering behind many of the things you use every day. The pieces are in depth but written in an easily accessible fashion. Each has useful illustrations and selected links to related resources. The pages are well designed and the author has paid attention to good HTML coding and image size so they load quickly too.
Topics cover everything from how to write Web pages to how cell phones work.
I for one just can't get enough of the high-resolution pictures taken with the Hubble Space Telescope. This site is NASA's official archive of publicly released images. There are hundreds of pictures organized in several dozen categories that cover everything from our neighboring planets to deep space objects and distant galaxies. Astronauts will be living and working on the station as it's built beginning in mid 1999. The International Space Station Web site covers all aspects of the project including details on the construction phase, bios of the first three crewmen and an outline of anticipated activities planned for the US component of the station.