I discovered this site that is trying to list all freeware and shareware touch typing tutors,
seems pretty comprehensive.

http://typingsoft.com/all_typing_tutors.htm

I thought the program Stamina was interesting for two reasons, it has training sessions that are about working on letter combinations and words that use them and it presents you with a graph at the end of instantaneous speed in cpm. 

Of course, downside is that it's qwerty, so it's not a tutor program to start with but it might be helpful once you have learned  the keyboard since the lessons at that stage are not keyboard specific rather language specific. 

The tendency graph is interesting,  when I was doing individual letters jfkd, it would initially peak at 130 cpm and decay to 110 cpm.  When I did letter combinations, it peaked over 350 cpm and decayed to around 240 cpm toward the end.