I wouldn’t use the word “rules.” Wicca has it’s tenets…. we don’t necessarily tout them as the best way or the only way… just as the Wiccan way. No one is forced to be Wiccan, or follow Wiccan teachings… no one is punished if they don’t; if they don’t, they’re just not Wiccan.
We don’t have scripture; we have liturgy. We have advice. We encourage people to think for themselves. Our religion is very experiential (note, that doesn’t mean “experimental.” It simply means the key to practicing Wicca is experiencing life and spirituality as a Wiccan).
Main facts about Wicca I guess are:
1) We honor the Higher Power(s) in the balanced forms of God(s) and Goddess(es). (Most important)
2) Our religion is fairly ritual; our rites fairly ceremonial, there is a certain general structure to our rituals, common tools, etc.
3) We celebrate the Wheel of the Year as we see it reflected in the cycles of nature and the cycles of our lives.
4) Our religion is nature based, as we see the Divine both as immanent and transcendent. We seek union with the Divine through our connection to nature.
5) Our moral teachings encourage us to strive for balance and harmony in our lives, to take personal responsibility for ourselves, to make good choices and consider the reprecussions of our actions. To have respect for others and their teachings, and take what we can learn from them.
I should add a great website: wicca.timerift.net