This free book from National Academy Press is a great introduction to teaching evolution meant for teachers. The attached chapter comes from Teaching about Evolution and the Nature of Science (http://www.nap.edu/read/5787). The book includes a readable overview of the important concepts to cover and includes lessons plans and strategies for teaching. The excerpt includes a fictional dialogue between teachers discussing whether to teach evolution:

Here’s a taste:

“Stanley will never believe in evolution.”

“We talk about ‘believing’ in evolution, but that’s not necessarily the right word. We accept evolution as the best scientific explanation for a lot of observations—about fossils and biochemistry and evolutionary changes we can actually see, like how bacteria become resistant to certain medicines. That’s why people accepted the idea that the earth goes around the sun—because it accounted for many different observations that we make. In science, when a better explanation comes around, it replaces earlier ones.

Follow the pdf link above to read the rest of the excerpt.

The book includes the following chapters:

1. Why Teach Evolution?
2. Major Themes in Evolution
3. Evolution and the Nature of Science
4. Evolution and the National Science Education Standards
5. FAQs about Evolution and the Nature of Science
6. Activities for Teaching About Evolution and the Nature of Science