There are a couple of books out there that explore the connections between astrology and myths. Planets and Possibilities by Susan Miller looks at the myths associated with each sign. There's also a book called MythAstrology by Raven Kaldera. I have yet to read it, but it looks like it goes much more indepth, exploring the myths associated with each possible planetary position.
My friend emailed me a link to an article by Raven Kaldera and on that site I found another article about astrology and mythology.