JavaScript tutorial at webdeveloper.com.
A good and thorough JavaScript tutorial, an alternative to Netscape documentation.

Netscape Navigator Resources Page
This is an index of Netscape resources, it includes several good manuals, specifications and articles. A javascript reference is a must-have.

www.webteacher.com/javatour/framehol.htm
A javascript tutorial, for beginners. I haven't read it, but based on other tutorials by the same guy, I bet it must be good.

Resources Page. Although webIGN resources page does not provide specific information on JavaScript, there are many links you can visit to learn more about JavaScript.