Hi,
I am web master trying to provide accessibility to our corporate website. I checked our site with <spam link> and it gave me a very comprehensive report. I would like to know if there are any similar free products available.
Here's a decent checker that works from WAI for 508 and WCAG. I find that a lot of them can't tell you specifically what is wrong or might be wrong an leaves you still with a bit of work to do, but it'll still catch some helpful things too. I recommend reading through the accessibility guidelines for 508 and WAI to get an understanding of things you should watch out for while you develop pages.