Why do Pagans wear a pentacle? Isn't it evil?

A huge misconception about the pentacle is that it is a symbol of evil - mostly due to the way that the media has portrayed it. The pentacle is made up of a five-pointed star - the line of which is unbroken - surrounded by a circle. It is a talismanic symbol, which has been in existence for thousands of years, found scratched on the walls of Neolithic caves or in Babylonian drawings, where it marks the pattern the planet Venus makes on its travels. Even early Christians used the pentagram - to them it represented many things, one being the five wounds of Christ. According to Pythagoras, the Greek mathematician and philosopher, five is the number of man, because of the fivefold division of the body, and the ancient Greek div of the soul- the five points each representing one of the five elements that make up man: fire, water, air, and earth, and psyche (spirit - represented by the topmost point). The circle, which surrounds the pentacle, represents the circle of life - the wheel of the year.

The inverted pentacle, with it’s point facing down, is not typically used by Wiccans, however there are still a few traditions who use it to represent their second level of training. However, they do not use it for evil purposes. That being said, however, the inverted pentacle is used by Satanists (just as they invert the Christian cross) to symbolize the triumph of matter and material desires over the spirit. Satanism and Wicca are two separate spiritual paths with completely different theological ideas and are never to be confused.
Many people get confused between the pentacle and the pentagram. The best way to remember is that a pentagram is a five-pointed star while a pentacle is a five-pointed star in a circle.