Cableguy, the Catholic church here organizes prison visits of the kind you have in mind. I expect some other churches and organizations do too, but your best way to find out about such things would probably be to call a Catholic priest at one of the churches here and ask him about it. If he doesn’t know, he could probably put you in touch with someone who does. I’m sure they’re always glad to bring in new volunteers to join them in this work, and I suppose it wouldn’t matter too much to them whether or not you’re a member of their church.