I've been using a text-to-speech program called TextAloud, along with an AT&T Natural Voices voice, to listen to my fiction be read back to me, and it's become a GREAT tool. The voice is pretty natural, though it strangely stumbles over a word or two here and there. I've mentioned it before, but now I'm hooked, and I always use it when editing. It has proven invaluable in helping me smooth out the rough areas in my fiction and catch most of the typos that are actual words.
Here's the way I work with it. In TextAloud, I open the Word file and it's loaded into the program. I click the SPEAK button and it begins reading the story back to me. I minimize TextAloud and open the file in Word and follow along, listening and reading at the same time...when something clangs or is just wrong, I can usually make the correction then catch up with the voice. If a major change needs to be done, I either make a note in the doc and keep going, or pause TextAloud while I make the revision.
I just edited two chapters in my novel, in a coffee shop (using headphones, of course). For some reason, this type of editing actually goes faster than the traditional means of editing...probably because, psychologically, I want to keep up with the voice so instead of dawdling over a crap sentence, I hone in on how to correct it immediately, as the other half of my brain listens to what the voice is saying. Strange, huh?
Anyway, I'm loving it.