Ringer.org - Ringer.org is a free ringtone maker to make ringtones from any song or audio file.

Audiko - Audiko Ringtones is a free to use mobile application that can help you customize your mobile phone by setting the most beautiful images your background and the most popular ringtones as your notification signals.

Switchr.net - Switchr is a free online audio converter site that lets you convert audio files on the fly.

MakeOwnRingtone.com - Make your own ringtone! Follow the steps:

Cool Sounds - Sounds Collection: Animals, Humans, Tools, Ultrasounds, Ringtones and more...

Song Cutter and Ringtone Maker - Free Online Ringtone Maker