Dvorak keyboard layout
Dvorak is a computer keyboard layout. It is designed to be easy, fast and comfortable (unlike the common keyboard layout called QWERTY.
Switching to Dvorak keyboard layout usually increases your typing speed by about %20, and reduces hand and wrist strain more than most ergonomic keyboards. Dvorak is also easier to learn than QWERTY.
You do not need to buy anything to use dvorak. You can do it with your normal keyboard. You just need to change a setting in your operating system to tell it to interpret your key presses differently.
MS Windows, Mac OS, GNU/Linux and probably others come with Dvorak. The Targus folding keyboard for Palm Pilot even comes with Dvorak support.
Here's more info about it, and how to set Mac OS to use it: