Asteroid Links:
IAU: Minor Planet Center (MPC) the MPC is responsible for keeping accurate records of all of the minor planets and Near-Earth Objects (NEOs) observed. The site is a vast resource for amatuer asteroid watchers, especially for those who think they may have found something new!
Oglethorpe Astronomical Association this site allows you to request maps for any of the 4,656 minor planets by name or catalog number. These maps will show you exactly where any asteroid is on any night!!!
Near-Earth Asteroid Tracking Home Page also helps you track the most visible of the minor planets.
NASA Asteroid Observation Page allows you to obtain a list of all observable asteroids based thier magnitude and your location for tonight.
NASA Asteroid Database
 
 

Near-Earth Asteroid Mining:
SPACEDEV is a private corporation that will be launching the first commerical probe between October 2000- February 2001.
PERMANENT(Projects to Employ Resources of the Moon and Asteroids Near Earth in the Near Term) is an online resource compiled by physicist Mark Prado.  This site contains detailed information about space resource development and a full description of a hypothetical mission.  It also has links to other valuable references.

Other Astronomy Sites and Tools:
Electronic Publications for Astronomers has lots of great resources all online!  They have Icarus and many other journals such as: The Astrophyscial Journal, The Astronomical Journal, and Astronomy and Astrophysics.
The University of Washington's Astronomy Department Homepage has lots of information. I especially like their online astronomy tools page.
Astronomy and Astrophysics has all A&A journals from November of 1996 to the present. It's updated very regularly!!!
US Naval Observatory Astronomical Applications Department gives you the exact time of moonrise & set, sunrise & set, civil twilight, astronomical twilight, and nautical twilight for your exact city!
Ames Astronomy Resource Page has great links to eclipse sites, occultion times, variable stars, etc.