I've learnt a lot on my Ergonomics degree concerning web accessibility and it does concern me that so many webmasters neglect it. There are various reasons for this like being used to tables rather than CSS and a lack of understanding of the problems. I don't know if people are aware, but the 50-60 age bracket spend the most, drink the most and are probably the worst catered for group on the net. So to speak, these are where the cash cows are and with the growing use of webTV and other easy to access ideas there's an opportunity to make a penny or two. The problem is many webmasters who are fully able are not thinking about less able users when they design the site. For a commercial site, this could be many lost purchases from able or less able users that struggled to navigate the site or read/find important information.

I found a massive list on the W3C site: Evaluation, Repair, and Transformation Tools for Web Content Accessibility

What I liked about this page is that the program suggested not only can it identify the problems they suggest others that can help fix it. Most of them I haven't tried or heard of so I'm currently preaching and not doing although I plan to upgrade my site again soon so that the errors are brought down significantly.

Rob