http://www.youtube.com/watch?v=z3Zsvml57PE is a video describing how to learn more about the Mormon Church.
This video has President James E. Faust, President Thomas S. Monson and President Gordon B. Hinckley talking about the tremendous sacrifice that the Mormon pioneers made in crossing the plains.
The Mormon pioneers were members of The Church of Jesus Christ of Latter-day Saints, also known as Latter-day Saints, who migrated across the United States from the midwest to the Salt Lake Valley in what is today the U.S. state of Utah. The journey was taken by about 70,000 people beginning in April 1847, and ending with the completion of the transcontinental railroad in 1869.
Since its founding in 1830, members of The Church of Jesus Christ of Latter-day Saints were often harshly treated and persecuted by their neighbors, primarily due to their inclination toward social and political unity and their unorthodox religious beliefs. There was violence directed against the Church, its members, and its leader, Joseph Smith. This among other reasons caused the body of the Church to move from one place to another- Ohio, Missouri, and then to Illinois where church members built the city of Nauvoo. Missouri Governor Lilburn Boggs issued an extermination order against all Mormons living in the state. In 1844 Joseph Smith was killed by a mob while in custody in the city of Carthage, Illinois. In 1846, religious tension reached their peak, and in 1848 mobs burned the Latter-day Saint temple in Nauvoo.
According to church belief, God directed Brigham Young, Joseph Smith's successor as President of the Church, to call for the Saints (as church members call themselves) to organize and head west, beyond the western frontier of the United States (into what was then Mexico). During the winter of 1846-47, Latter-day Saint leaders in Winter Quarters and Iowa laid plans for the migration of the large number of Saints, their equipment and livestock. This major undertaking was a significant test of leadership capability and the existing administrative network of the recently restructured Church. For his role in the migration, Brigham Young is sometimes referred to as the "American Moses."
Brigham Young personally reviewed all available information on the Great Salt Lake Valley and the Great Basin, consulting with mountain men and trappers who traveled through Winter Quarters, and meeting with Father Pierre-Jean De Smet, a Jesuit missionary familiar with the Great Basin. The wary Young insisted the Mormons should settle in a location no one else wanted, and felt the Great Salt Lake Valley met that requirement but would provide the Saints with many advantages as well.
Information from Wikipedia. For more information, visit http://www.mormon.org