In addition to the Book of Mormon, there are two other main sources of doctrine in the Church of Jesus Christ of Latter-day Saints:
Doctrine And Covenants contains 136 "revelations" from God, many of which are not accepted by the Reorganized group -- including polygamy, the Temple Lot, etc.
This book contains a blatantly blasphemous claim that "Joseph Smith, the Prophet and Seer of the Lord, has done more, save Jesus only, for the salvation of men in this world, than any other man that ever lived in it." (D and C, 135:3).
I find it very interesting that this book "divine command" for Mormon elders to debate in public: "Wherefore, confound your enemies; call upon them to meet you both in public and private; and inasmuch as ye are faithful their shame shall be made manifest." (D and C, 71:7; D and C, 71:2e, Reorganized version). Around 1990 I had a debate on the radio with a Mormon elder from England. This young man was disciplined by his "bishop" for engaging in a debate and sent back to England! The command to publicly debate their enemies is one command that Mormons have no problem ignoring!
The Pearl Of Great Price is usually bound together with Doctrine and Covenants, and sometimes both of these books are bound together with the Book of Mormon.
In 1835 Joseph Smith purchased some ancient Egyptian manuscripts. Smith "translated" one of the manuscripts and published the Book Of Abraham and The Pearl of Great Price. Part of The Pearl of Great Price is similar to the Biblical book of Genesis.
In 1967 the manuscripts were really translated by real Egyptologists and it turned out to be a book of funeral descriptions called the Book Of Breathings. It does not mention Abraham, his religion nor any Bible characters which Smith claimed for it -- Smith was a simply a false prophet and liar.
The Reorganized branch does not recognize The Pearl of Great Price as a part of God's revelation.
The Truth About Mormonism, the largest of all American cults, the Church of Jesus Christ of Latter-day Saints (the Mormons) has grown to a worldwide membership of over 11 million people -- yet it began in 1830 with just six members. This sixteen page booklet contains two sermon outlines on this cult (PDF file size: 264k).
Also, you can listen to David Padfield and Mormon elder Paul Meade debate the "Inspiration of the Book of Mormon." This debate on Mormonism is available as an MP3 file from this website.