I am a Parish Nurse in my local church. I attending a year long class at a hospital locally beforehand, but that is not mandatory for starting a program in your church. The Lutherans were the first to pioneer the parish nursing specialty. You can set up the program about any way you want to meet the specific needs of your church population. However, PN does not include doing any type of invasive procedures. It is primarily health counseling, screening, and organizing and training various types of volunteers to meet the needs of the congregation.
Most church insurances cover medical liability only for non-licensed personnel. In other words, nurses must have separate coverage. Only one insuror of churches, Brotherhood Mutual, has an endorsement that is perfect for the PN, and costs very little. Other churches cover their PNs by providing professional liability coverage or requiring the PN to carry their own.
Several books are available to assist in learning about and setting up a PN program. All of mine are at church right now. The only one I can come up with by memory is by Granger Westberg (the pioneer of PN) and I think it is called Parish Nursing.
The program I went through does not pay any salary to myself. However, they do employ some of their graduates in community centers. One program in Knoxville, TN, pays all of their graduates full salary their first year after graduation in their church, half salary the next year (the church pays the other half), and then 1/4 (I think) salary the third year. By the fourth year, the church is expected to pay their full salary. I do PN as a volunteer service in my church and work another job.

Good luck! It can be a big undertaking and sometimes frustrating, but the rewards are wonderful!