In addition to Google's site, there's an excellent FREE online "school" called Codecademy. There your child can set up an account and learn 7 different computer languages and how to build a website. Codecademy has them learn languages one step at a time, creating projects along the way.
Do you have a child that would like to start a website or a blog? Check out weebly.com or blogspot for easy, inexpensive ways to get them started. *Please be sure to remind them how public these forums are, and spend time monitoring those accounts. The internet can be a very, VERY dangerous place for our kids!*
Spend some time checking out these sites and you can introduce your children to some great summer fun!