Ringer.org is described as 'free ringtone maker to make ringtones from any song or audio file'. There are five alternatives to Ringer.org, not only websites but also apps for iPhone, Mac and Android. The best alternative is Audiko, which is free. Other great sites and apps similar to Ringer.org are Vidm8.com (Free), Song Cutter and Ringtone Maker (Free), Create Ringtones! (Freemium) and i39 (Paid).
Vidm8 is a free and simple online service for converting videos from Youtube to mp3. It even can create ringtone from Youtube video. It can also convert to mp4(iPhone, iPad video format),flv, webm, ogg, 3gp. It is optimised to be used with smartphones!
i39 is a lightweight and efficient OS X app that manages to reduce the whole ringtone creating process to a few mere mouse clicks. With i39 you can create many gorgeous unique ringtones from your favorite songs.