On AjaxDeveloper.org today, there's this new post with a pointer to an Evolt.org article released today about the creation of a login form with Ajax (and some help from PHP).

I started a project on the weekend that I wasn't sure was possible: creating a fully secure "ajax"-powered login system, ideal for blogs, forums, and other similar sites. I had a barebones secure case working within a few hours, and a few more hours gave the final result that I will share today.

They talk about how it's all structured, how the Ajax and PHP work together to make it happen, and what the end result looks like. They also link to a demo of the scripts where you can also download the pieces to get your own login working...