My latest MSDN article is now available, and focuses on Web site accessibility. Making ASP.NET Web Sites Accessible talks about accessibility guidelines - the WCAG and Section 508 - as well as Microsoft's quiet release of an ASP.NET HOTFIX that fixes a number of Section 508-related accessibility issues. The article also examines how to extend the ASP.NET Web controls to improve their accessibility. Specifically, the article illustrates how to improve the DataGrid class so that it will support sorting in browsers that do not support JavaScript.
In addition to this article, I also presented a talk on accessibility at the San Diego Day of .NET Conference back in April 2004. You can download the slides to this talk here.