These links are a collection I have found useful over the years. While
some of them refer to specific information, most direct you a good
starting point for resources on that particular subject.
Picture of the Day
X Prize Competition - Scaled Composites won 10/2004
Hubble Space Telescope Pictures
NASA - the US government space program.
SETI@home - the Search for Extraterrestrial Intelligence at Home
Comets & Meteor Showers - about them and when they're visible.
Extrasolar Planets Encyclopaedia