Astronomy Resources - good sources of links to general resources in astronomy, including web sites, netcasts, celestial news stories, organizations, telescopes and observing resources, cool images, software, and more. From the University of Hawaii IfA Library.
AstroWeb - a collection of pointers to astronomy-related information available on the Internet, maintained by the AstroWeb Consortium. You can browse or conduct a powerful search for sources on this site. Resources are listed by category, including organizations, observing resources, data resources, and more.
International Astronomical Union
Astronomical Society of the Pacific
PhysLINK - Daily physics and astronomy news, large reference section with constants, conversions, quotations, as well as information for teachers.
WebStars: Astrophysics in Cyberspace - intended as a resource for users who have a general interest in astronomical topics, maintained by NASA's High Energy Astrophysics Science Archive Research Center (HEASARC): Education and Public Information.