Dear EASI,
Bobby has become well know as a web page accessibility evaluator.   It is a product that was created by CAST, Center for Applied Special Technology. http://www.cast.org/  Under CAST, Bobby could be downloaded for free.    However, the product was turned over to Watchfire and for more than a year has cost about $100.  The software is now going to cost $300 for a single user version after May 7.  Please see Axel Schmetzke's email to this listserv.  

Bobby is a good program, but it is not the only web accessibility evaluator.
First, let me say that all accessibility evaluators require the user to make decisions about the accessibility of the page.   No evaluator will automatically assess all web accessibility criteria.  Please look at the W3C site on how to evaluate a web page.  http://www.w3.org/WAI/eval/

The W3C also has a list of software tools, some free and some pricey that will assist you in assessing web pages. http://www.w3.org/WAI/ER/existingtools.html#General

Richard