"What is behind the Wiccan mystique?" Catherine Edwards Sanders tries to answer this question in an excellent book called Wicca's Charm. Written from a Christian point of view, the author has done her homework in probing the reasons that teens and women raised Christian are turning to this pagan world view, knowing full-well that the myths surrounding it are myths (history made of whole cloth) and that it's nothing more than "create your own God/ess."
Part of the attraction is the shallowness of pop culture, the thirst for ritual, the empowerment that girls/women seek, and the exotic, earthy nature of Wicca. I'll write a fuller review shortly, then an article, but in the meantime, I highly recommend this book as an intro. One cannot engage in discussion about the meaning of life without understanding what wiccans accept and reject, even if there is no dogma under which they operate.
If your kids aren't playing with this, their friends are. Arm yourself.