The Disability Resources and Educational Services (DRES)
at the University of Illinois at Urbana-Champaign has released a new version of its online Web Accessibility Evaluation tool.
This is a rather neat bit of code that can be pointed at a site and will spider down to third-level links within the site, producing a report at the end.
You can access the Functional Accessibility Evaluator here. Please note that registration is required to make full use of this tool.