Donna Maree Hanson has been trying to write a novel using dictation software, and just posted an article about her experience:
Well I was working on my novel a couple of months back and my hands hurt but I really wanted to keep writing. So in desperation I put on my headset and started dictating a scene and it worked and I did it. Just like that. I made the cognitive leap. I’m not saying I prefer it over using my hands to type, but that I could dictate a scene.
If you are looking to write by dictating your word-babies, this might be helpful: http://donnamareehanson.wordpress.com/2012/12/04/dictation-software-breakthrough/