From 4Videosoft Studio:
4Videosoft iPhone 4S Ringtone Make is especially designed for iPhone 4S users to make iPhone 4S ringtone. With this professional iPhone 4S Ringtone Maker, you can easily convert any audio/video/DVD file to iPhone 4S M4R ringtone. You can also add M4R ringtone to iPhone 4S directly.
Moreover, this iPhone 4S Ringtone Maker enables you to edit iPhone 4S ringtone freely. And this iPhone 4S Ringtone Maker highly supports all iPhone devices and iOS 5.1.