My son has started keeping a blog. I won't post the link here, not until he's ready to publish it. For now, it's a personal exercise for him.
Here are some good blogs of people I know:
My Scientology
Eclectic Stuff
Mom Kat
The Lab
Swirl
Garters
Equivoque
Food: A heavenly sin
Good News
I really encourage anyone teaching children how to write to find two particular books: "Putting it in Writing" which is published by Scholastic, and "Everything You Need to Know about English Homework" which, despite it's title, is actually a very good resource for learning about writing.