PBS recently produced a 4 hour documenatary series about the Mormons (torrents). An accurate and fairly respectful work, it does gloss over some of the stranger sides of Mormon theology. Mormonism is in many respects an American Muslim styled religion although this parallel is completely ignored by the documentary and probably most Mormons themselves. South Park had a very good episode "All About the Mormons" from Season 7. Given that Mormons now even have a US Presidential candidate, they are worth understanding.