Font created to help dyslexic readers. Bottom heavy and unique character shapes help make it more difficult to confuse letters.
OpenDyslexic(open-dyslexic) by Abelardo Gonzalez is licensed under a Creative Commons Attribution 3.0 Unported License.
This means, as long as you visibly give credit, you can use this on your ebook, ebook reader, actual physical books, web sites, etc.
Included are 3 styles of OpenDyslexic: OpenDyslexic, OpenDyslexic w/ alt rounded a's, and OpenDyslexicMono: for your fixed-width font needs.
Updated to fix printing issues in Yosemite. See sources for details.