Install on Sony Reader

See instructions here:

http://blog.the-ebook-reader.com/2010/09/22/sony-font-hack-how-to-change-fonts-on-a-sony-reader/

Also, the sony reader supports embedded fonts in ePubs. You can embed open-dyslexic in your ePub books, and view them without having to use this hack. It's much cleaner, and you can share those ePubs with others more easily.