A new beta release of Nokia's Ringtone Maker, version 1.2.5.6, is now available through Nokia Beta Labs. The app lets you create ringtones from the (DRM-free) music stored on your phone. A simple editing interface lets you cut the ringtone in any way you like by specifying the start, end, and length of the ring tone. Once you've created and named the ringtone, it can be saved, and, optionally, be set as your current ringtone.

The new beta release adds support for the MWA, M4A, WMA, and AAC file formats, complementing the existing support for MP3, and allowing a wider range of music files to be turned into ringtones. In addition there are a number of bug fixes, which improve the stability and usability of the app. 

Windows Phone Store description:

With Ringtone Maker, you can create ringtones from the music on your phone. Simply open the app, select your favorite song and save it as a ringtone. You can cut your ringtone anyway you like, with editing controls that let you choose the start, end and length of your ringtone.

In this version there’s now support for more music file formats: WMA, M4A, M4R, and AAC along with MP3.

Ringtine Maker, which is exclusive to Nokia Lumia devices, can be downloaded from the Windows Phone Store. This latest beta release is only available for Windows Phone 8 devices, but an earlier version is available for older Windows Phone 7 devices.