Asteroids
Links
IAU: Minor Planet Center
http://cfa-www.harvard.edu/iau/mpc.html
We are the official body that deals with astrometric observations and orbits of minor planets (asteroids) and comets.
Minor Planet
Dediced to minor planets and astronomical imageing. Contains information on minor planets, building observatories and robotic telescopes and remote systems.
Small-Body Orbital Elements
http://ssd.jpl.nasa.gov/sb_elem.html
from JPL/NASA. Provides access to orbital elements for the numbered asteroids, unnumbered asteroids, and comets contained in JPL's DASTCOM database.
The Asteroid Orbital Elements Database
ftp://ftp.lowell.edu/pub/elgb/astorb.html
astorb.dat is an ASCII file of high-precision osculating orbital elements, ephemeris uncertainties, and some additional data for all the numbered asteroids and the vast majority of unnumbered asteroids (multi-apparition and single-apparition) for which it is possible to make reasonably determinate computations.