A free program for Android, by Zinn App Studio.

Mp3 Music Cutter is the best music cutter and ringtone maker app for Android users. It is very easy to use and it has a user-friendly interface. With this app, you can create a new ringtone from your own voice or from any audio file in your device. The app supports many audio formats, such as mp3, ogg, flac, wav, aac, etc. 

To create a new ringtone, you need to select an audio file from your device and then select the area you want to cut. After that, you can save the file and set it as the default ringtone. You can also edit it and change the pitch.