Go ahead and wince at these technologies...I work for a company that builds and hosts these sites when your IT group will not/cannot get it done. Several of our clients are government organizations, and they are begging us to push this kind of envelope. Also, AJAX/Flash and Sect 508 compliance are not mutually exclusive. A properly built website will degrade gracefully and screen readers and web crawlers alike will see useful content. Using a framework like Symfony (http://www.symfony-project.com/) makes such functionality very easy to implement.