The Popcorn Board - Lots of information on the history and growth of popcorn.  Even an address to send away for free lesson plan ideas.

Popcorn Snack Recipes - Easy to do in the classroom! 

The Huckabuck Family and How They Raised Popcorn in Nebraska and Quit and Came Back by Carl Sandburg.
The story of a farming family and their ups and downs.

Popcorn by Alex Moran.
An easy-reader, rhyming book.

The Popcorn Book by Tomie de Paola.
A fun book filled with true facts on popcorn and its history.

The Popcorn Dragon by Jane Thayer.
A story of how a dragon makes some friends by popping corn with his fire breathing mouth.

Popcorn at the Palace by Emily Arnold McCully.
The blended fact and fiction story of a young girl and her father who travel to London to try and interest the English in popcorn.

Popcorn Plants by Kathleen V. Kudlinski.
A nonfiction book with an abundance of information and real photographs of popcorn plants.

Science Fun With Peanuts and Popcorn by Rose Wyler.
Fun experiments, recipes, and activities to be done with popcorn and/or peanuts.

Why Does Popcorn Pop?: And Other Kitchen Questions by Catherine Ripley.
A collection of questions and answers to some commonly asked "kitchen questions".