I have found some dyslexics can improve their reading if they don't need to scan lines to read, particularly those whose difficulties seem to be cerebellar or parietal (visual spatial) rather than phonemic. Software that is designed to help people speed read can be used to help some dyslexics, e.g.
http://spreeder.com/index.php
works electronic texts, or you could look at:
http://alternativeto.net/software/spreeder/
These are not designed to improve dyslexia, but they may help dyslexics read with less effort - more of an aide than a therapy...
I've created a comprehensive overview on assistive technologies for dyslexia and related difficulties on: http://www.dyslexiaaction.org.uk/assistive-technologies
I also write a regular blog on this topic on http://www.dyslexiaaction.org.uk/tags/tech-thursday.