Gee, thanks, guys! 8-)
Actually, I was about to suggest CoasterQuest; he's got some good stuff in there, and much better illustrations than I have.
Another place to look is Victor Canfield's patents page. I don't have the URL handy, but he's got lots and lots of roller coaster related patents. You want to know how any of the mechanical components work, you can look at the original patent drawings linked from Victor's site.
As for my own site (linked above), I've got articles in there on blocking theory, car chassis designs, linear motors, and this summer's incident on Superman: Ride of Steel at SFNE.
If you have specific questions, I suppose I could come up with something, but I can't make any promises. :)
--Dave Althoff, Jr.