There's a large number of threads about this.
Try this one,
http://www.mp3car.com/vbulletin/software-software-development/18675-not-sure-if-repost-not-but-dragon-naturally-speaking.html
Or
for either Voiceflux or Dragon Naturally, or "voice control" etc...
As far as mic's are concerned, you need a boom mic for the best results. One of the ones that you wear, otherwise the ambient noise confuses it. The cheaper ones don't seem to pick up as well either.
Good luck, keep up posted.
Kris