The Ajax Lessons blog has a nice tutorial on Building Tabbed Content using a mix of JavaScript and PHP.

Here’s a real gem! The Yahoo! UI Library is a collection of JavaScript libraries that have been released as open source under a BSD license and are free for all uses!  The library contains libraries for DOM scripting, HTML, AJAX and a set of really cool UI widgets.

moo.ajax is a small and awesome JavaScript library that will make embedding AJAX calls in your web applications very easy.  I’ve been using this library for the past couple of weeks, and have found it to be great to work with.  It’s based on the popular Prototype JS library, but is much smaller in size (3K) so is a perfect solution if the full Prototype library add too much overhead.

The Particletree weblog has a great tutorial on Preloading Data with Ajax and JSON.  This is a neat technique to help speed up the responsiveness of your web applications.

This has got to be one of the greatest Firefox Extensions aimed at the Web 2.0 developer. FireBug is a docking pane that essentially replaces the Firefox DOM Inspector, JavaScript Console and HTTPRequest Sniffer all in one fell swoop.  The pane docks against the document loaded into the current tab or window and shows information only for that page.  The best part is that the DOM inspector included with this tool is far simpler and more powerful than the one installed with Firefox.  Go get this one now!

Web develolper Pete Freitag offers a nice concise AJAX Tutorial using Prototype - a popular JavaScript library.  The tutorial walks you through the steps to create a live zipcode lookup widget.

Another advent calendar worth reading is 24 ways. Again a post every day from December 1 to December 24 except this calendar post totally awesome general web development tutorials.

Wow - here’s some pretty cool uses for AJAX. In a three part tutorial, security schemes are created that:

• Use mouse gestures in place of passwords
• Use keystroke detection to foil non-human bots
• Building an AJAX captcha

I think there are some serious usability issues with parts one and three, as I must admit that I was unable to make them work (mostly an eye/hand coordination thing) but they are none the less cool and worth checking out.

Agave Group has released a very good Priority / To-Do / Keep-track-of-stuff List web application. It’s a pretty slick open-source product that uses lots of AJAX mixed with PHP and MySQL. The download info is available in a separate post.

Dynodes use CSS, unobtrusive Javascript, and the Document Object Model to create, import, run, and destroy foreign script nodes on demand, without the usual security restrictions faced by AJAX.