The main Scriptaculous site is, of course, at script.aculo.us. Amy Hoy has a wonderful cheat sheet for Scriptaculous at her site, slash7.com, which covers the basics and can help get you up and running.

Scriptaculous is based on Prototype, of course, and the home page for Prototype is prototype.conio.net. This site contains almost nothing other than the Prototype code itself; not even documentation is located here. A reference guide to Prototype is at www.sergiopereira.com/articles/prototype.js.html, which is a good starting point for experienced JavaScript and Ajax programmers.