Everett Zufelt (aka @ezufelt) is the Drupal 7 Core accessibility maintainer. He is an assistive technology user himself, and was working with Mike Gifford and Open Concept to help improve the accessibility of Drupal 7.

Zufelt talks about some of the differences between the Web Content Accessibility Guidelines 1.0 and WCAG 2.0. He also discusses the accessibility implications of JavaScript, jQuery UI, and the Drupal 7 Admin Overlay as related to the Accessible Rich Internet Applications Suite (WAI-ARIA) recommendation.

Zufelt also was selected to present at the Drupal Core Developer's summit on the topic of "Don't Sink the Accessibility Boat" (PPT).

He also talks about the Common Look and Feel for the Internet 2.0 (CLF 2.0) standards set by Canada for their government sites.

Finally, Zufelt talks about tracking Drupal issues tagged with "Accessibility", as well as how he intends to create a portal page on Drupal.org at http://drupal.org/accessibility with more information on Accessibility. It currently doesn't exist yet, but in the meantime you can check out the Accessibility Group on g.d.o. for more information on Accessibility and Drupal.