Web Content Accessibility Guidelines 2.0 (WCAG 2.0) covers a wide range 
of recommendations for making Web content more accessible. Following 
these guidelines will make content accessible to a wider range of people 
with disabilities, including blindness and low vision, deafness and 
hearing loss, learning disabilities, cognitive limitations, limited 
movement, speech difficulties, photosensitivity and combinations of 
these. Following these guidelines will also often make your Web content 
more usable to users in general.

          http://www.w3.org/TR/2008/CR-WCAG20-20080430/

www.peoplewho.org