In the 80s, I learned how to touch type by playing Infocom games like Zork.
The key to learning how to touch type is just typing _a lot_. You might not be very fast (I'm not), but you can at least get your eyes off your keyboard and use more than one finger per hand.
>The key to learning how to touch type is just typing _a lot_.
Absolutely. I don't think that typing-tutor software really does very much teaching at all, it's just a good tool for drilling yourself. But why not have fun in the process, rather than boring and mindless drills? I learned by playing the early Sierra adventure games, before they switched to the all-point and click interface.
Now I'm feeling all nostalgic...time to go download ScummVM.
In fact, the only other memetically famous touch-typing software I know of is Typing Of The Dead¹, and that's not exactly widely-available.
¹: http://en.wikipedia.org/wiki/The_Typing_of_the_Dead