PBS has some outstanding sites that include lessons about predator and prey relationships, supply and demand, and adaptations:
From the PBS series, "Living in Eden":
The Wolf and the Moose Through role playing and research, students will learn about predation in the Alaskan wilderness.
How Many Birds Would it Take to Keep a Jackal Alive? Through a classroom game, learn about predator-prey relationships and food supply and demand.
How Can I Hide in Namib? Compare the methods used by different animals in Namib to escape predation.
Also from PBS - Etosha: Prey or Pray? Could YOU Escape a Cheetah?
Students will learn about the size and speed of cheetahs through video and still photographs.
The Raptor Center from the University of Minnesota includes several activities about the interdependency between predators and prey. It also includes lessons on understanding how people form attitudes about the environment, wildlife and predators. Lesson Plan.
University of Arizona Center for Insect Science provides information sheets and lesson plans in English and Spanish.
Wildlife Links for educators from Deer Flats National Wildlife Refuge
Kids do Science lessons from the University of Georgia.
Head to Wolfquest for information on predators including a PowerPoint Presentation