Starry Vistas by Don J. McCrady
Microsoft Research's WorldWide Telescope is a wonderful new tool for viewing imagery, exploring the solar system & cosmos, and learning about the wonders of the night sky.
A friendly community of astro enthusiasts.  Lots of general photography interest as well.
Articles, equipment reviews, forum discussions, galleries, and loads of information about all aspects of amateur astronomy.
AstroPhoto Insight Magazine Bi-monthly e-magazine featuring useful articles by some of the most respected astrophotographers out there.
Astronomy Picture of the Day A daily showcase of some of the best professional and amateur images out there.
Sky & Telescope My astronomy magazine of choice.
Astronomy Magazine Astronomy Magazine, also a fine publication.  Popular forums as well.
Clear Sky Clock Clear Sky Clock: Weather predictions made by and for astronomers.
Royal Astronomical Society of Canada Canada's premier astronomy organization.
Skyhound Skyhound contains lots of fascinating observing information, and is also the home of SkyTools 2, highly recommended observing planner and logging tool.
Bud's Astrophotography Bud Guinn's astrophotography page, with articles and an impressive gallery.
All About Astro - Jay Ballauer Jay Ballauer's excellent astro site, with a great gallery of shots, and many useful articles.
Darkfire Observatory Mike Hernandez' observatory and gallery.
Mike's Astronomy Site Mike Reid's astro site.  Lots of good equipment information.
All About Light Pollution An excellent site about light pollution and things you can do about it.