If you've ever ring tones for your iPhone, you know that iTunes can convert various music formats to M4R, the ring tone format. What you might not know is that the process works in reverse as well, turning ring tones back into music files. Change an M4R file extension so that iTunes views it as a music file and then convert it to MP3.
Right-click the ring tone in iTunes 12 and choose Show in Windows Explorer to open the Windows folder containing the ring tone file.
Open the View tab in Windows 8 and turn on File Name Extensions. Select the ring tone file, press F2 to rename it and change the extension from M4R to M4A.
Drag the file with the M4A extension into the iTunes window to add it to the library as music.
Open the iTunes Preferences in the Edit menu -- or press Ctrl-Comma. Click Import Settings on the General tab and choose MP3 Encoder from the Import Using drop-down menu. Set the quality level and click OK on both open windows.
Right-click the song in your iTunes music library -- not in the tones library -- and choose Create MP3 Version.