When Mormons talk about conversion, they are talking about something much deeper than someone changing from one church to another. We are talking about the Holy Ghost actually testifying to the individual about the truthfulness of the restored gospel, coupled with the desire to repent, and enter into a sacred covenant with Jesus Christ through the ordinances of Baptism and receiving the Holy Ghost.
Some mistake our missionary work as merely an effort to get people to join our church. The truth is that Mormons are interested in getting others to join the church, but only because we believe that it is the true church of Jesus Christ and the only place on earth where Jesus has authorized men to perform the sacred ordinance of Baptism through the holy priesthood, thus giving people the only real opportunity to come to Jesus Christ.
In order to come to Jesus and receive salvation, one must have faith, repent, be baptized, and receive the Holy Ghost. (Acts 2:37-38)
In order for baptism to be recognized by the Lord, it must be performed by one who has the proper authority to baptize. This authority to baptize is called the Aaronic Priesthood. It is the same priesthood that the Levite priests were given by God in the Old Testament. In order to give the Gift of the Holy Ghost by the laying on of hands, those laying hands must also have the proper authority. This authority is called the Melchizedek Priesthood. It is the same authority that the apostles of Jesus had in order to lay hands and give the Gift of the Holy Ghost. (Hebrews 7)
The reason that Mormons want you to join the church is so that you can truly come to Jesus Christ and experience the only organization on the earth where these two priesthoods, given by the Lord exist.
If you want to be saved and enter Jesus’ Kingdom, you must come to Jesus in the way that He said to come. This requires Faith, Repentance, Baptism (by the proper authority, only found in the church), and receive the gift of the Holy Ghost (the authority to confer this gift is also only found within the church).
That is the simple reason we want you to become a member, it’s because their is no other way to come to Jesus fully and receive His mighty Grace.
Jesus said:
“6 Jesus saith unto him, I am the away, the btruth, and the life: no man ccometh unto the Father, but by me.” John 14:6
We know that the only way to the Father or to Heaven is through Jesus. But before Jesus can take us to the father, we must first come to Jesus. And the only way to come to Jesus, is through Faith, Repentance, Baptism by the proper authority, receiving the Gift of the Holy Ghost, and enduring to the end.
In order to truly go through this process, you just join the church. That is because it is the only place you can receive baptism and the Gift of the Holy Ghost in a fashion that will be accepted of the Lord. Because it is the only organization on earth where the holy priesthood of God is.
In the name of Jesus Christ Amen.

The problem I find is that the LDS line of “authority” in founded on false prophets. Sandra Tanner gives a very good explanation of this fact: http://www.utlm.org/onlineresources/howdowetestaprophet.htm
note: Sandra Tanner is the great-great-granddaughter of Brigham Young.
Joseph Smith fails the test and Brigham Young fails the test. Brigham Young believed the Sun and Moon were inhabited see: Journal of Discourses 13:271
Brigham Young:
“Who can tell us of the inhabitants of this little planet that shines of an evening, called the moon? When we view its face we may see what is termed “the man in the moon,” and what some philosophers declare are the shadows of mountains. But these sayings are very vague, and amount to nothing; and when you inquire about the inhabitants of that sphere you find that the most learned are as ignorant in regard to them as the most ignorant of their fellows. So it is with regard to the inhabitants of the sun. Do you think it is inhabited? I rather think it is. Do you think there is any life there? No question of it; it was not made in vain. It was made to give light to those who dwell upon it, and to other planets; and so will this earth when it is celestialized.”
Barry,
Joseph Smith and Brigham Young were true prophets of God. Both Joseph and Brigham actually do pass the test of a prophet with flying colors. Sandra Tanner is actually a relative of mine through her husband Jerald. The articles you site by Jerald and Sandra were produced to distort the facts greatly and set up straw men arguments. Jerald and Sandra have been shown to be the true frauds by both LDS and non-LDS scholars alike.
1. The Journal of Discourses is not doctrine of the church and is in no way binding on the members because it was written largely by sources that were not first hand and cannot be relied upon.
2. Here are a few good articles that deal neatly with the issues you have brought up:
Prophetic Test: http://en.fairmormon.org/Joseph_Smith/Prophecies/The_prophetic_test_in_Deuteronomy_18
Brigham Young and “Moon Men”: http://en.fairmormon.org/Brigham_Young/Teachings/Moon_and_sun_are_inhabited
If you want to know the truth about Mormonism, I invite you to pray sincerely about it and I testify to you that you can know that it is true by the power of the Holy Ghost. If you are not sincere, and don’t have real intent, God will not bless you with the answer. But if you are sincere and are willing to act upon whatever God tells you, He will give you the answer that it is His work and it is true.
The source of my knowledge is the Holy Ghost and I know the God does not lie.