We bought our then-9-year-old a Trek MTB - it's purple and was the "girl's version" according to the sales guy, but it's plenty sturdy and can be adjusted quite a bit as she grows. She's 11 now and has grown about two inches in height since we bought it, and Dad has had to move her handlebars and seat accordingly. Last year she and I rode the Tour of Poway together (18-mile course) and we're training for it again this year. I'm hoping she can do the 26-mile course this time.
She'll be read for a road bike in a couple of years. It may very well be that she'll get a commuter bike instead of a commuter car when she turns 16. Ha!
Roxy
Getting in touch with my inner try-athlete.