The best thing you can do if you want to learn more is to actually read the myths in their original contexts. The following is a list of books and links to help you do just that. I have noted the best translations where possible. Everything in this list is HIGHLY RECOMMENDED.
If you have only one myth book on your shelf, this is the one you should own. It has everything. It is well-researched. HIGHLY RECOMMEND.
Funk & Wagnalls Standard Dictionary of Folklore Mythology and Legend Ed. Maria Leach. New York: Funk & Wagnalls Company, 1949
Great book, but way more than just Greek. Lots of value, even though its seriously old school (and problematic).
Graves, Robert. The Greek Myths. England: Penguin Books, 1992
Pretty much discredited as an actual resource by academics (and, now, me), his exploration of Greek myths is fascinating and big on women, mysticism, and fraught with suggestions of a matriarchal prehistory.
Guerber, H. A. Greece and Rome: Myths and Legend. London: Bracken Books, 1986
HIGHLY RECOMMEND!!! This book is great for beginners and experts. It is SUPER readable without lots of notes or citations, but helps you understand the subject at a truly advanced level. And let me tell you, this is a juicy juicy topic that will also help you speak intelligently about sexuality today! Also, I reviewed it in my blog. (Full disclosure: He was my professor.)
Osborn, Kevin and Dana L. Burgess. The Complete Idiot's Guide to Classical Mythology. New York: Alpha Books, 1998
Not just for idiots, but totally digestable. VERY informative. HIGHLY RECOMMEND.
Oxford Classical Dictionary: Second Edition. ed. N. G. L. Hammond and H. H. Scullard. London: Oxford University Press, 1970
Penglase, Charles. Greek Myths and Mesopotamia: Parallels and Influence in the Homeric Hymns and Hesiod. New York: Routledge, 1997
Pomeroy, Sarah et al. Ancient Greece: A Political, Social and Cultural History. USA: Oxford University Press, 2007.
A balanced and complete overview of ancient Greece. Read it in college. If you want history, start here.
This site inspired me to make my own. I am sad that it is gone. All the sites that are crossed out have disappeared from the connection of tubes we call teh interwebs, but I may have gotten information from them before they did. Obviously, these days, I try to verify all my info in original sources, but I've been at this a long time.