MochiKitA lightweight Javascript library
http://www.mochikit.com/ Best Practices in Javascript Library DesignThis talk explores all the techniques used to build a robust, reusable, cross-platform JavaScript Library. We'll look at how to write a solid JavaScript API,...
http://www.youtube.com/watch?v=0LKDImgRfrg JavaScript KitYour comprehensive JavaScript, DHTML, CSS, and Ajax stop
http://www.javascriptkit.com/ CodingForums.comJavaScript programming
http://www.codingforums.com/forumdisplay.php?f=2 The Yahoo! User Interface Library (YUI)The Yahoo! User Interface (YUI) Library is a set of utilities and controls, written in JavaScript, for building richly interactive web applications using techniques such as DOM scripting, DHTML and AJAX. The YUI Library also includes several core CSS resources. All components in the YUI Library have been released as open source under a BSD license and are free for all uses.
http://developer.yahoo.com/yui/