Existing Systems

There are almost no systems that exist on the web that actual teach the user how to touch type, the main systems that are on the web are used to improve the users speed. This is normally done by using a text based tutorial and then a test that gets them to type a sentence that they then get a speed at the end of the test.

Tutorial

One system that demonstrates this is at sense-lang.org where you put in a sentence of your choosing you are then asked to type it, if you hit the incorrect letter you are shown where the keys are on the keyboard that you should be pressing.
This system also gives the user a WPM score as they go along but does not give the user a total at the end so the user cant see there speed unless they stop typing and look at the speed they are going at.
http://sense-lang.org/typing/tutor/English.html

WPM calculator's

jonmiles

This is a system that i found that lets the user actual find out what there wpm score is by doing a 6 minute test and at each section of the test they are displayed there current wpm score and at the end they are given a total score and encouraged to go to a tutorial site to improve there score.
This system does not display multiple words so the user does no know the next word that is coming, and on its own there is no tutorial but is is a good way to find out the users score at the end.
http://www.jonmiles.co.uk/fingerjig.php

calculatorcat
This system lets the user see the sentence they are going to be typing before they type it, but does not give a score at the end unless you tell it to stop and the system lets you make some errors. This is the system i used for my test as it was shorter.
http://www.calculatorcat.com/typing_test/

Books

There are many books that can teach to touch type but they require the user to copy out lots of letter's which is not very interesting and my target audience would get bored after the first page as it is page on page of typing asdfg asdfg asdfg.
The book below is one of the more popular books and shows the hand positioning and has lots of test for the user to do but as young users my target audience would not get far before lousing interest unless they where forced to do it.
http://www.amazon.co.uk/Touch-Typing-Ten-Hours-Dobson/dp/1845283406/ref=sr_1_2?ie=UTF8&s=books&qid=1236553380&sr=1-2

PC Games

The pc games all have lots of examples and let the user go at any speed, but there biggest downfall is that you need to be on a pc where you can install the system. Many of the systems on the market also have long lessons for each sections of the keyboard which your only option is to leave the game should you want to stop.
http://www.amazon.co.uk/Teaching-you-Touch-Typing-2-PC/dp/B000ODSZPK/ref=sr_1_1?ie=UTF8&s=software&qid=1236554314&sr=8-1