It's hard to distinguish fact from fiction about Voodoo in New Orleans. This shop in the French Quarter is one of several in the city. Many claim a large number of residents of the city practice the voodoo arts, brought to the area in the 1700's from Africa via Santo Domingo (Haiti) or other Carribean stop overs. Santo Domingo was said to be the birth place of the the famous Voodoo queen, Marie Laveau, of who tales and legends abound.
There is no doubt that a marketing industry has built up around the superstitions, healing charms and spells of the religion -- such as this site.
If your curious, I might suggest this article from Wikipedia -- which is usually a pretty reliable source since it is peer reviewed.