A free program for Android, by Super Effect Studio.

Voice Changer is the best way to sing like a star. With the app, you can create cool, funky, and unique sound effects using different voice effects. All you have to do is record your voice and apply the effects you want. You can use the app to make cool music or record a message for your friends. 

It has more than a hundred different effects to choose from, including:

Recording and editing: The app can automatically record your voice, so you can edit it and change the tone. It also has a recording editor, where you can change the pitch and speed.