A Dvorak keyboard is basically just a keyboard with the letters layed out in a different arrangement.
CLICK HERE TO SEE THE LAYOUT They say the advantages are mainly in a user's typing speed because its sorta optimized by placing the vowels and highest usage consonants on home row, instead of staggered all over like a normal QWERTY setup. It's supposed to be easier for new typists to learn too. I never have used one myself because I learned the QWERTY setup and that's all I've ever used, so I figured trying to reteach myself to use the Dvorak would just mess me up. Plus the fact that since its not as widely accepted as the QWERTY is, if you got a job in an office or somewhere that you had to use a computer, it would most likely still be the QWERTY layout.