I hope you don’t mind me just copying and pasting the definitions. I am awfully tired at the moment :P

Wicca:  A polytheistic Neo-Pagan nature religion inspired by various pre-Christian western European beliefs, whose central deity is a mother goddess and which includes the use of herbal magic and benign witchcraft.

Paganism: More recently, the definition of Paganism has evolved yet again to become a general term for the followers of magickal, shamanistic, and polytheistic religions which hold a reverence for nature as a central characteristic of their belief system. It’s also given rise to the term neo-pagan (literally ‘new pagan’), which refers to a follower or sympathizer of one of the newly formed pagan religions now spreading throughout the world.

Obviously it goes way deeper than that, there are many different kinds of Pagans and Wiccans.