Alternative History
Alternative History Webwring
Point of Divergence (Alternative History 'zine)
GURPS Alternate Earths
GURPS Alternate Earths 2
Alternative History from Del Rey(part of Random House)
Uchronia
Alternative History Travel Guides
Stephen Abbott's Alternative History Site
Pteranodon's View
Doug Hoff's Alternate History Site
Jim Ritter's Alternative History

Space
NASA
European Space Agency (ESA)
DLR - (National German Aerospace Research Center and Space Agency)
Russian Space Agency (RKA and VKS)
Chinese Space Agency (unoffical)
People's Republic of China Missle & Space Forces
National Space Development Agency of Japan (NASDA)
Canadian Space Agency
SETI Institute
The Planetary Society
National Space Society
Space Frontier Foundation
Space.com
Mir
International Space Station
IKI (Russian) Space Research Institute
The Nine Planets
The History of Rocketry

Authors/Books
Adventure Fiction
Fantasy Authors
Science Fiction Authors