Summarize:

Before deciding to join the Amish, it is imperative that you learn as much about their religion, history, and lifestyle as possible. The Amish communities of today are descendants of Swiss Anabaptists who emigrated to the United States in the early eighteenth century.  There are approximately 250,000 people living in Amish communities across North America.  The largest Amish community is in Holmes County, Ohio; although there are other sizable Amish populations in Pennsylvania, Iowa, Indiana and smaller communities across the Eastern and Mid-Western states, as well as in Canada. Amish is a stricter branch of the Mennonite Anabaptist Church, with which it shares many beliefs and practices. The Amish, with other Anabaptists, reject infant baptism in favor of adult baptism, giving an adult the right to choose their religion and commit to joining the Amish community. The Amish refer to themselves as the "plain people" and to anyone outside of the Amish community, regardless of religion or race, as "Englishers" or "high people". There are many informative websites and books available that cover every aspect of Amish life. You should do your best to visit an Amish community as part of your research. This will give you some insight into what the day-to-day life of an Amish person is like. Despite popular belief, there are no restrictions on "English" people visiting Amish communities. You can visit Amish businesses and converse with the people, most of whom will be willing to answer any questions you might have.  It may even be possible to stay in a bed and breakfast run by a local Amish family. This will give you an even closer look at the Amish way of life, which places God and family above all else. If possible, try to visit several communities on your trip, as different Amish communities will vary slightly in terms of their customs, traditions, and level of strictness and you will need to find the one to which you are best suited. If you cannot travel to an Amish community, you may be able to set up correspondence with an Amish person to gain an insight into their beliefs and way of life. The Amish do not allow computers or, in most cases, telephones, so communicating by post will be your only option. Remember to respect their beliefs and do not take any identifiable photographs of them (the Second Commandment, Exodus 20:4 - "Thou shalt not make unto thee any graven image..."). They may allow you to take pictures of their buggy or farms if you ask politely, however.  Be aware that some may not feel comfortable (especially women) with talking to outsiders extensively about their faith or lifestyle since they are taught to be modest in everything they do. After visiting one or several communities, you need to decide which community you would like to join. Once you have developed a short list of about 3 to 5 communities, you should begin contacting the leading bishop of each community to gauge whether you would be welcome to join their church. Finding the leading bishop should not be too difficult; if the community is on your short list, you have probably already visited it and hopefully developed some contacts there who can help you.  Although the Amish do not have any rules forbidding outsiders from joining, it is highly unusual and typically not encouraged, so contacting the bishop is a good way to judge what the community's reaction to a newcomer is likely to be.  If the bishop is open to the idea of you joining their community, he will invite you for an interview, where you can put forward your reasons for wanting to become a member of the Amish. You will need to demonstrate the strength of your faith, your willingness to renounce the ways of the modern world, and your commitment to the Amish way of life. As long as your motives are pure and you are fully aware of what life in an Amish community entails, there should be no objection to you coming to live in the community. Once you have made your decision and you have received the bishop's permission, you may begin your new life as a member of the Amish. You will first be placed with an Amish family, where you can learn their ways and participate in the household duties. During this time you must prove yourself to the Amish by living according to their religious principles and becoming a productive and valuable member of the community. Once you have done this (there is no set time period), you may be voted into the church and become a true member of the Amish community.  Unless you are coming from another branch of the Anabaptist Church with a very similar lifestyle, you are likely to find the transition to Amish living somewhat difficult. Living without electricity, cell phones and motor vehicles is a lot harder for someone who is used to having these luxuries, than it is for people who were brought up in the Amish community and don't know any differently. Although some Amish may be very welcoming and helpful to you as you make your transition, others may be more distrustful of you and not expect you to last very long. Give them time. Once you prove your faith and commitment, they will grow to trust and accept you.
Learn as much as you can about the Amish. Visit an Amish community. Decide if you still wish to join. Move into an Amish community.