It called lexercise at http://www.lexercise.com. I have not don the actual testing, but it offers a free simple screening that takes 10 or so minutes. They also offer some reading support through their technology.
Personally, I think the value of understanding if you are dyslexic is so valuable. Many tests can cost up to $5000. this offers a free test and full evaluation for about $500. It's worth looking at.