I recommend the following books for students who want to find out more about evolutionary developmental biology. Both books are quite accessible and written by leading biologists in the discipline.
Sean Carroll, Endless Forms Most Beautiful: The New Science of Evo Devo (Norton, 2005).
Neil Shubin, Your Inner Fish: A Journey into the 3.5-billion-year History of the Human Body (Pantheon, 2008)
The Wikipedia entry, part of a series of pages on evolution, provides a good brief overview: http://en.wikipedia.org/wiki/Evolutionary_developmental_biology.