Mark Pilgrim's http://www.diveintoaccessibility.org/ http://www.diveintoaccessibility.org/ is a good starting point, though it's out of date (2002) with respect

Mark Pilgrim's http://www.diveintoaccessibility.org/ http://www.diveintoaccessibility.org/ is a good starting point, though it's out of date (2002) with respect to the AJAX-y stuff that the post is talking about here.