The web is filled with excellent astronomy resources. Here are some of the sites I frequent for different kinds of information.
Visit daily: Astronomy Picture of the Day
Photos and Images: NASA has a wealth of photos from all of its missions.
Eclipses: the authority on all things related to eclipses: Fred Espenak's NASA site
Good for listening: StarDate is a quick daily dose of very general astronomy topics. Astronomy Cast is an excellent weekly podcast for those looking for deeper insights.
General Resources: Sky and Telescope Magazine or Astronomy Magazine are very good portals covering many aspects of astronomy for the amateur and hobbyist. Spaceweather.com has very useful up-to-date information and news about the goings-on in space.
Sun and Sky Conditions: The Clear Sky Clock provides a wealth of detail on sky conditions with details on transparency, darkness, seeing, and so on. The US Naval Observatory provides exact sunrise and sunset times anywhere on the globe.
Clubs: San Francisco Amateur Astronomers have a range of activities and resources if you want to get more involved in astronomy.