This site could well be the best electronic typing tutor I've ever seen -- it blows away Mavis Beacon and pretty much every other digital typing training I've tried in the last couple of decades. The site is clean, the lessons are superb, and you can step through them in logical order (learn a row at a time, move on to punctuation, throw in numbers, then speed drills, etc) or skip around and work on whatever suits your fancy. There are also typing games, short stories and headlines to retype, and detailed reports on your progress. It even supports alternative keyboards, like the Dvorak.
The site is all the more amazing because it's free (you can circumvent ads by paying a one-time $10 fee) and you can even skip registration if you want to (though registering gets statistics and saves your place). If becoming a better typist is one of your career-improvement goals, you can do a lot worse than TypingWeb.