There are two main types of school gardens:  teaching gardens and production gardens. Of course there is a wide variety of designs and approaches to each, and lots of  examples of how students can be involved each step of the way.

Joseph Kiefer and Martin Kemple, Foodworks at Two Rivers in Montpelier, VT wrote the book (Digging In)  on teaching gardens.  Foodworks also has many other great publications on the topic.

Across the country in Berkely, CA the good folks at the Edible Schoolyard also have lots of resources based on their experiences.

Watering the peas under the stick trellace