Wiccan Belief?

I have been in and out of the Wiccan belief becuase I was born a Mormon. I have studied and learned from the Wiccans. However, something doesn't sit right with me. I have noticed that some of the Wiccans have the Pentagram upside down, like as Satanic, what does that represent? Is it banishing? Because I thought it was that you belive more in the power of Fire and Air..?