Site accessibility: what screen readers, etc to test against, and how?

The web site that we're writing needs to be "Accessible". The trouble is, while we understand the general conepts (semantic latout, alt text on images, light on Javascript, etc etc), we don't really have much knowledge of what screen reader products or other accessible browser are actually on the market and/or in general use, nor how to test against them.

So the questions are:

What products do we need to know about?
Would it be sensible (or even useful) to get hold of them to test against?
Are there any QA processes we should be looking at to assist us (we do a lot of automated browser testing [Selenium] to ensure we don't break anything for regular users; can we/should we do the same for screen readers?)

Thanks in advance for any tips.

Solution

See this question As the question implies if you want good screen reading testing you either need to hire someone to do the testing for you that has a lot of screen reader experience or invest the time in having developers and or QA learn a screen reader well. To my knolidge there is nothing like Selenium that can simulate how a screen reader handles a website. FOr general info on accessibility see http://www.w3.org/WAI/gettingstarted/ This appears to have a lot of good information and covers all kinds of accessibility, not just blindness. For a list of tools to check html accessibility see http://www.w3.org/WAI/ER/tools/complete.html Although these tools will help they are not a substitute for screen reading testing. For a discussion of some of the problems with relying only on automated tools see http://www.webcredible.co.uk/user-friendly-resources/web-accessibility/automated-tools.shtml