My kids all loved BBC Mat typing (it's called something like that - don't remember the exact name!). It's online and free. The recommendation we've had is to not stress if your child doesn't want to follow conventional touch typing rules, let them figure out their own adaptive system. (FWIW, mine stuck with the traditional, against all the advice we had!) Once they'd been through the very basics of learning to type instruction, the best practice was simply letting them type whatever they wanted to - emails to family members, playing games that required typing, writing stories etc on the computer.
polarbear
