Well, a truly basic
website, if you know
nothing is
How Stuff Works.
A more advanced site is
The Car Bible.
A nice site for beginners is the one at Monroe:
Suspension systems, or the
Technical Training (really basic) page.
If you are more "into it", I also like the site at
Racing Car Technology for the basics of shock absorber tuning. It's interesting to compare that site with
the one they wrote many years ago, where the errors are in yellow.
Finally, do not tell anybody outside the Internets that if you go to The Pirate Bay and search dynamics you could get a copy of the book on Car Dynamics by Springer. God, forgive me... (God might forgive, but RIA won't).