Tutorials

Most of the information on this site is helpful. See the Greasemonkey Manual for starters.

Greasemonkey tutorials

Warning: these are both several years old.

• Greasemonkey hacks (as a wiki)
  
• Monkey see, GreaseMonkey do! - Video tutorial for GreaseMonkey userscript development

JavaScript tutorials

• Mozilla's JavaScript Guide
• tizag's JavaScript Tutorial
• JavaScript on QuirksMode
• The JavaScript Programming Language (part 1, 2, 3, 4) by Douglas Crockford
  A set of videos of a wonderful lecture by this JavaScript guru.
  You can check Crockford's JavaScript dedicated website at http://javascript.crockford.com/
• JavaScript Closures for Dummies
• JavaScript Closures

JavaScript references

Once familiar with the language, one may notice there are many available features in JavaScript which are initially hard to remember.

• MDC, an extensive wiki from Mozilla which details JavaScript and Firefox-unique features alike
• Gecko DOM Reference
• w3schools JS reference

JavaScript Books

• JavaScript: The Definitive Guide is well regarded
• For a modern introduction to JavaScript, check out John Resig's Pro JavaScript Techniques