Build Your Own Rollercoaster

It's from the Discovery Website for Kids, but hey, fun is fun... HERE'S THE LINK.

ALSO: Atari's software, "Rollercoaster Tycoon" (various incarnations/versions)

Various websites:

Welcome to Ultimate Rollercoaster.com, the definitive online destination for Roller Coasters, Theme Parks and Thrill Rides.

Funderstanding Roller Coaster - Java applet designed to teach about the physics of roller coaster design. Users alter several variables to achieve maximum excitement and safety.

Roller Coaster DataBase - The rcdb is a comprehensive, searchable database with information and statistics on over 1800 roller coasters throughout the world.

Software: Thrill-Filled Roller Coaster Simulator - NoLimits is the ultimate roller coasters simulation game that let´s you experience authentic roller coaster thrills. Focusing on realism and speed, NoLimits lets you ride real existing coasters, or build rollercoasters to your own specifications - with 18 different track styles, including inverted, hyper-coasters, wooden and shuttle coasters.

Play Online: Fantasy Rollercoaster - Miniclip.com