A free program for Android, by Weasel.

Ghost Voice Box is a mobile app for people who are interested in paranormal activity. This app allows you to communicate with the dead using your voice. It’s a simulation of a ghost detector, so you can get in touch with the surrounding energies! You can use it alone or within a group environment. The app is useful for entertainment purposes only, and it simulates a ghost detector tool.

The first thing you need to do is prepare a space, free from distractions and noises. It’s best to use headphones or over speakers. The second thing is to open yourself mentally and spiritually. You need to do this in order to be able to communicate with the dead.