Traditionally... wiccans are all good... in my mind, if you do evil things or are a 'black witch' if you will, you are NOT wiccan. But that's just my opinion and perception of wicca.
There are many bad, or off track people who CLAIM they are wiccan, but as I said... people like that clearly are not, they just like the name association. Like a lot of the goth kiddies who run around now adays saying they are wiccan but yet know NOTHING about the history, or rituals of the religion past "I'm a witch, and wiccans can cast spells!"
Wicca is not the soul religion out there in which people think of when referering to witches and such, there are others out there, probably more commonly known is Pagan.
If you want a quick run down of what a wiccan is basically suppose to live their life by in general "rules", then read the Wiccan Rede.
Mom of 10: Oh, and that's soo adorible! haha, what better for earthly creatures then an earthy religion... more things that make it hard for me to grasp the traditional christian god theory.