AJAX Libraries API - Google Code
Google is now hosting all the major JavaScript libraries. The caching benefits should be good news for your users.
Tags: scriptaculous
rikrikrik: Wasted Javascript
How much page weight is being wasted on JavaScript. It's time to shed those pounds.
Infovore : <%= javascript_include_tag :defaults %> considered harmful?
A cautionary note to Rails coders from Tom. The default JavaScript includes can really add to your page weight. Only include them if you really need all of them.
The JavaScript Library World Cup [JavaScript & DHTML Tutorials]
Dan Webb does an excellent job of comparing the big four JavaScript libraries that were discussed at @media.