A lot of Greek myths in alphabetical order - read them all!
To find out more about Greek mythology, check out these books from Amazon or from your library:
Greek Myths for Young Children, by Heather Amery (Usborne, 2000). My niece really likes this one. For younger children.
Greek Myths for Young Children, by Marcia Williams (1995). In comic-book format. My son loved it.
D'aulaire's Book of Greek Myths, by Edgar and Ingri D'Aulaire. For older kids.
Mythology by Lady Hestia Evans, Dugald A. Steer (Editor)(2007) - My daughter loved this one! A new book in the Fairyopolis, Dragonology, etc. series.
Pandora's Box: A Three-Dimensional Celebration of the Mythology of Ancient Greece, by Sara Maitland and Christos Kondeatis (1995). Not really about Pandora specifically, but a complex of stories, games, and puzzles about Greek mythology. All ages.
Greek Religion, by Walter Burkert (reprinted 1987). By a leading expert, for adults. He has sections on each of the Greek gods, and discusses the deeper meanings of the Greek myths, and their function in Greek society.
Teaching and Dramatizing Greek Myths, by Josephine Davidson (1990). Advice for middle school teachers on teaching Greek myths by having the students write and perform skits.