mediAvatar Ringtone Maker 

mediAvatar Ringtone Maker allows Mac users to make ringtones in MP3, WAV, M4R, AMR, AMR (3G), M4A or OGG format from almost all video and audio formats (including AVI, MPEG, WMV, DivX, MP4, H.264/AVC, AVCHD, MKV, RM, MOV, XviD, 3GP, MP3, WMA, WAV, RA, M4A, etc.) on Mac, regardless of your mobile phone models (iPhone, BlackBerry, Google phone, Windows Mobile, Nokia, Motorola, Sony Ericsson, LG, HTC or others).

Want to make your ringtones special? Add fading effects and adjust ringtone parameters. Or only want part of your video or music as ringtone? Clip the segment you want and convert it to ringtone.