The first thing you need to do is to choose an instrument.
If you look around your area, most likely you will find at least several organs in churches within 50 mile radius. To increase your chances of securing the place, I recommend you get to know the local organist, go to church service, compliment him or her for the work he or she does. Then you can introduce yourself and say you would love to play a recital in that church.
When the church doesn't have the organist, sometimes you can get to know the priest or a pastor of that congregation. Introduce yourself and your idea to play a recital.
Make sure you satisfy the idea of "What's in it for me?" which will likely pop into priest's or organist's head. Try to be honest and tell the truth what you can do for the congregation. Something along the lines, that you want to give the people joy of experiencing sacred music, lift up their spirits etc.
Never forget that your recital is not about you but about the people you want to serve. Also remember that there are priests who don't want to hear secular music in their church so make sure you talk their language, too.
The spell-word is "sacred music".