Max Kiesler ha creado una larga lista sobre interesantes articulos sobre accesibilidad con ajax.

AJAX is a great tool for creating rich internet applications, however, when improperly implemented it can cause hugh accessibility issues. The good news is that most of these issues can be fixed so your websites are viewable by a much wider audience. Great resources on accessibility have been around for years, however, many web 2.0 and AJAX websites ignore all of the research that went into turning website accessibility into a movement followed by most professional web developers. Below you’ll find a list of 40 best AJAX accessibility tutorials and articles that I have found on the web in the last year.

La verdad, unos cuantos son un poco toston pero los siguientes me han parecido interesantes:

Accessible JavaScript Guidelines
Use Javascript to enhance the usability features for the majority of users, without negatively affecting the accessibility for the minority of users. You can almost always fall back on a plain HTML or server-side solution for the benefit JavaScript provides.
AJAX and Screenreaders: When Can it Work?
We’ve all heard a great deal of buzz about AJAX in the last few months, and with this talk has come a legion of articles, tips, presentations and practical APIs designed to explore the possibilities and try to arrive at best-practice techniques. But, for all of the excitement and hype, still very little has been said on the subject of AJAX and accessibility.
JavaScript Accessibility Examples
Use the event handlers on an anchor element rather than on the image element. An image cannot achieve keyboard focus so it would never be able to use the keyboard events.

Usability and accessibility with Ajax
The Ajax express train rumbles on, threatening to crush anything in its path. Recent discussion has turned to those critical elements of good web development, usability and accessibility. Accessibility is a major issue with Ajax, mainly because anything that relies on JavaScript to function is inaccessible pretty much by default. There are two solutions: either provide a fall-back system where the site remains useful without its Ajax enhancements, or provide a whole separate interface that works without scripting.

ajaxian.com