THAT my friend is a very good idea! The younger the better, as from what little I know as a child gets older it gets harder for them to learn a new language.
I had to take a French class in high school...what a disaster that was.
Five years of high school French looked great on my applications for college. I also had two years of high school Spanish. Colleges like the fact that a student sticks with a language for four full years; this predicts future success in college because it shows you can set a goal and fulfill it. They also like to see two years of a second language, it shows the student committed to mastering the basics of that second language.