If this has been discussed before, sorry; I didn't find it in a search.
At some point, TextAloud should support epub format. Project Gutenberg appears to be adding it as a supported format. A very nice program I am using called Caliber changes many formats into epub. The Sony Reader also appears to support epub. FBreader, one of the better readers,
It seems to be the happening free reading format these days, so TextAloud should of course be part of it, I think.