John Hopkins University
Developer of a range of spacecraft and scientific payloads providing project overviews, scientific and engineering articles.

Launchdate
Offers an updated list of coming launches, and links related to launch conditions.

Space and Astronomy Reference Links
Provides a space and astronomy related directory.

FAST
Provides directory with validated and graphics-free entries, compiled the National Space Society, USA.

Russian Space Web
News and history of the Russian space program by Anatoly Zak, a journalist.

Space Travel and Exploration
News, information, and resources about space exploration for the armchair space traveler.

Encyclopedia Astronautica
Comprehensive resource providing articles on most space technology subjects and space flight history.

NASA Skywatch Sightings Calculator
A Java applet that will calculate when spacecraft will be visible in the night sky over the viewer's own location.

Space Projects and Info
Offers a collection of popularized material on space projects and astronomy. Includes forums and merchandising.

Heavens Above
Real-time satellite, ISS, and Space Shuttle orbital pass information, maps, and star charts.

BBC - Space
Features a variety of resources for space exploration and introduction to space flight. Includes many interactive and 3D animated views.

Jump from Space.
Features a Russian project to sky-jump from space (over 40km altitude). Includes background of the project initiator, Mogamed Tolboev.

European Space Industry Directory
ESID is an ESA database of more than 400 space companies and 1000 products.

Space Links
A good list of Space-related links.

Usenet space archive
Large collection of google group postings on all aspects of space exploration and development.

SpaceRef.com
Offers updated news selections, directory and collected reference material.