It took a bit longer than it did the last time I switched (I'm older now, I guess), but I think my transition to the Dvorak keyboard is nearly complete. I now "think" in Dvorak - my fingers are naturally finding the right keys without any intervention. Most of the time. Occasionally I have to pause to think about where a letter is - mostly when entering passwords or shell commands.
The biggest stumbling blocks at the moment are the slash keys ( /=\ ) and their shifted counterparts ( ?+| ) which tend to slow me down mostly when editing code (html lately - haven't been spending much time hacking real code lately).
I had to use the old home computer to check email this evening, and found the antiquated QWERTY layout absolutely furiating. It makes no sense whatsoever, once you've seen the light of Dvorak.
So, now I'm about 75-95% of my previous QWERTY touch-typing speed, and seemingly getting faster every day. Wrists feel fine, too. See ya, QWERTY!