Well to be honest I can test my code in IE9 to see if it works. But I have no idea how a disabled person is experiencing my website, I do put all the "alt" attributes etc...but it's hard to imagine it.
There are probably many groups already doing this stuff. Perhaps they just need better organisation or SEO?
Both are easy and free.
Color Oracle is a cross-platform app for the same purpose, though I haven't used it much, yet: http://colororacle.org It seems rather good in my limited testing.
Colour Contrast Analyzer is a Windows/Mac app for testing whether text/background contrast is sufficient. This is a matter of both color and brightness - a color combination that looks fine for a normally-sighted user may he completely unreadable for others for a variety of reason. (Part of why everyone's suggesting designers avoid the gray-on-gray or light-gray-on-white design hipster crap.)