My kids have used the BCC typing but didn't stick with it.
My kids have learned a little typing at school in computer class. Once my son had a little foundation for typing and could use 10 fingers he was more interested in doing something with typing rather than drills.
Here's some ideas, in word processing program, have him make poems, or type spelling words, write a story, send email, participate in Chat. My son despite his slow typing did a lot of typing of a story for a gifted online writing class last year. He has always been one to want to run before he could crawl type.
http://www.typing-lessons.org a typing web site,
http://www.spellingcity.com,
he can type in spelling words here. This is a nice way to practice typing with out getting over whelmed with a big project.
I would suggest if he is done with his school work early have him practice typing at school.