The Pentagram means different things to different people. Some may argue as to what it represents, but I will tell you the real meanings of it. The Pentagram right side up represents God ruling over the world of matter. The 5 points represent the 5 places that Christ was wounded. This is why Devils are afraid of it! It also represents the Microcosmic man with his arms stretched out.
Let us not forget that it also represents the elements Spirit, Water, Air, Earth, and Fire as shown below.
This is used by most people in Witchcraft.
Now there is also the upside-down Pentagram. It represents Satan or the world of matter ruling over God. It is the same as denouncing God. To wear it is to attract evil around you. It will not bring good spirits around you. Normally it is only worn by Satanists or devil worshipers. So if you wish to attract good spirits around you... wear it right side up!
Here we have an example of both the right side up and the reversed Pentagram...
Right side up (God ruling) Upside-down (Evil ruling)
Many mainstream religion believers think that they are both evil and represent the Devil. But that is because they are so... ignorant and blind to the fact that there is a difference. It shows their lack of study on the true facts of history.