I was just trying out the latest Ubuntu 8.10, named Intrepid, and you might be surprised, I was. They seem to have a new ( to me anyways) option under Applications called Universal Access, and it runs something called the Orca Screen Reader and Magnifier. It uses the Flite style voice to read whatever you position your mouse over, thru the soundcard. There are alot of options, and I only briefly tested it. If used in conjunction with the "High Contrast Large Print Inverse" theme, it is pretty handicap friendly.

You might want to check it out.