A free program for Android, by AndroidRock.

Ringtone Maker – Audio Cutter is an audio editing tool for Android phones. It is designed to help you easily create ringtone from any music you have on your device.

It allows you to cut audio, combine audio, convert to mp3, mix two mp3, create ringtone from wav, ogg, m4a, aac, flac, etc and save it to mp3, wav, m4a and acc. You can use third-party apps to scan, find and open music. It also provides support for mp3, wav, ogg, m4a, aac, flac, etc and convert videos from avi, mp4, 3gp, mkv, asf, flv, wmv, mpg, etc to mp3, wav, m4a and acc.