Today, Microsoft and HiSoftware are pleased to announce the release of the Accessibility Kit for SharePoint (AKS) v2.0. The AKS v2.0 provides an accessible development framework and significantly reduces the level of effort and knowledge needed by customers and partners to improve the accessibility of SharePoint based sites and applications.
See http://blogs.msdn.com/sharepoint/archive/2009/03/09/announcing-the-accessibility-kit-for-sharepoint-aks-v2-0.aspx for further details...