Wondershare Software has released its first professional audio/video
converting software — iPhone Ringtone Maker for Mac
(http://www.imediacreator.com/mac-iphone-ringtone-maker.html), which
can be used to make free iPhone ringtones.

Almost any audio/video format is supported by the program, and all
the ringtones made can be transferred to iPhone directly. You can add
fade in/fade out effects. The app offers professional wave-form
adjustment and direct connection with your iTunes library,
Wondershare iPhone Ringtone Maker for Mac also provides users with
ringtone management.

iPhone Ringtone Maker for Mac costs US$19. It requires Mac OS X 10.5 or higher.