Paganism
The words paganism and pagan come from the Latin "paganus," meaning "country dweller." Neopagans hold a reverence for the Earth and all its creatures, generally see all life as interconnected, and tend to strive to attune one's self to the manifestation of this belief as seen in the cycles of nature. Pagans are usually polytheistic (believing in more than one god), and they usually believe in immanance, or the concept of divinity residing in all things. Many pagans, though polytheistic, see all things as being part of one Great Mystery. The apparent contradiction of being both polytheistic and monotheistic can be resolved by seeing the God/desses as masks worn by the Great Mystery. Other pagans are simply monotheistic or polytheistic, and still others are atheistic.
Some people believe paganism to be a religion within itself; others see it as a belief system (such as monotheism) that can be incorporated into religions like Wicca or Druidism; others see it as a broad category including many religio ns. The fact that we are re-creating religion for ourselves after centuries of suppression makes us very eclectic and very concerned with the "rightness" of a particular thing for the individual. So when you see some people calling it a religion and others not, when you see it capitalized in some instances and not in others, don't be confused -- we're all still basically talking about the same thing.
Different types of paganism
Paleo-paganism: the standard of paganism, a pagan culture which has not been disrupted by "civilization" by another culture -- Australian Bushmen modern (who are probably becoming meso-pagans), ancient Celtic religion (Druidism), the religions of the pre-patriarchal cultures of Old Europe, Norse religion, pre-Columbian Native American religions, etc.
Civilo-paganism: the religions of "civilized" communities which evolved in paleo-pagan cultures -- Classical Greco-Roman religion, Egyptian religion, Middle-Eastern paganism, Aztec religion, etc.
Meso-paganism: a group, which may or may not still constitute a separate culture , which has been influenced by a conquering culture, but has been able to maintain an independence of religious practice -- many Native American nations, etc.
Syncreto-paganism: similar to meso-pagan, but having had to submerge itself into the dominant culture, and adopt the external practices and symbols of the other religion -- the various Afro-diasporic traditions (Voudoun, Santeria, etc.), Culdee Christianity, etc.
Neopaganism: attempts of modern people to reconnect with nature, using imagery and forms from other types of pagans, but adjusting them to the needs of modern people:
From alt.pagan FAQ