UPDATE - Since this blog post more information has been released about accessibility in SharePoint 2010 on the official SharePoint blog: http://blogs.msdn.com/sharepoint/archive/2010/03/09/accessibility-and-sharepoint-2010.aspx
After a long wait we can now announce that SharePoint 2010 has greatly improved accessibility with WCAG 2.0 support. I am out in Las Vegas at the SharePoint 2010 Conference and Steve Ballmer announced the WCAG 2.0 support during his keynote to great applause.
For a full overview of SharePoint 2010 check out this blog post from the SharePoint team http://blogs.msdn.com/sharepoint/archive/2009/10/19/sharepoint-2010.aspx. As i get more details about the accessibility support and other bits I will post them up.
Just one thing to note… the accessibility support is for WCAG 2.0 released earlier this year, not the original WCAG standard. For a quick overview take a look at the post ‘New W3C accessibility standard released’