Easy as Pie Ajax Requests - Create compelling ajax in minutes with simple examples. | Notes from Phazm
This is a good straightforward hands-on explanation of Ajax: succinct and clear.
perl.com: Using Ajax from Perl
My fellow Brightonian geek, Dom, has written an article about using Perl and Ajax.
Related links
MiniAjax.com / A showroom of nice looking simple downloadable DHTML and AJAX scripts
A collection of scripts. There might be some good stuff here but use with care and discretion.
Vitamin Features » Go forth and API
Cameron has written a great article on using APIs with Ajax. I love the idea of using .htaccess to fake a proxy and get around the same-site restriction.
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.
For Many AJAX is Not Degrading, But it Must :: Off the Top :: vanderwal.net
"...it must degrade well. It must still be accessible. It must be usable. If not, it is a cool useless piece of rubbish for some or many people."