Elizabeth Millard has written a very nice piece about speech recognition for Newsfactor.com and I recommend it highly.
It's rather obvious that speech recognition is advancing faster than handwriting recognition is. That's a shame because I can easily imagine the tablet PC with good handwriting and speech recognition as THE machine for the road warrior to have. (This even though that person is going to be the absolute least desired seat-mate on the airplane, unless they start letting folks use their cell phones during flights.)
There has been a lot of steady progress made since I was fooling with Via Voice in SuSE Linux 6.2. I'm half tempted to get one of the companies mentioned in the article to cough up a sample so I can see just how far things have come.