This series introduces Logo programming for beginners. These 12 challenges are written for you to work through at your own pace.
You don't need to know anything about programming at the start: you will learn enough at the first stage to write your own programs, and you may surprise yourself by how much you can achieve right away.
Windows users can download a free copy of FMSlogo.
A good free version for Mac users is ACSlogo.
There's a version you can run directly in your browser at http://calormen.com/logo/.