From Avgo International:
AVGO Free Ringtone Maker is a free software that lets you create your own ringtone from almost any audio or video file format.
It is a fun and entertaining tool which will definitely bring out the musical genius in you. AVGO Free Ringtone Maker has an easy to use interface that allows you to clip a portion of the audio from your favorite audio or video files as input, such as .mp3, .m4a, .wav, .wma, .avi, .flv (YouTube Format), .mp4 (iPod Video Format), .wmv, .mkv, .rm, .ra, .mov, DivX, XviD, 3GP and then convert it to ringtone format compatible with iPhone, Samsung mobile, Nokia mobile and more.
It also supports batch conversion and audio effect such as fade in and fade out.