Touch typing is one of the most useful skills you can acquire behind a keyboard. If you write regularly, then it's virtually essential, especially if you're a secretary or have to take notes over long periods of time. The advantages of touch typing are that you can see exactly what you write as you write it and most importantly of course, speed.
One of the most popular programs to help you learn is Ten Thumbs Typing Tutor. This simple and easy to follow program is suitable for all age groups so it's a good solution for the whole family. You can learn using full and proper QWERTY or Dvorak tuition with U.S and British keyboard support. A particularly good program for kids is GS Typing Tutor which aims to teach those 9 years and up how to touch type through a series of playful games. A more unusual and quirky approach is that taken by RapidTyping which recreates an underwater world within which to teach you the tricks of the trade.
A more professional package is TypingMaster Pro which promises to help users type up to four times faster than at the start of the course. Finally, if you're convinced you'll never be able to touch type but just want to increase your speed, TypeFaster takes you through a number of tasks designed to get your fingers working overtime.