How to Put MP3 Music on an iPhone as a Ringtone
Users have been able to customize ringtones on their cellular and smartphones for years. Now that phones like the iPhone come equipped with MP3 players, it's possible to use the MP3 music as ringtones. Adding MP3's as ringtones on your iPhone might seem a little complicated at first, but the entire process should only take up a couple minutes of your time.
Things You'll Need
Open your iTunes music library from the desktop of your computer and select the song you would like to set as a ringtone.
Right-click on the song and select "Get Info" from the pick list. A window detailing the song information will appear.
Choose the "Options" tab at the top of the window and enter the times you wish to have the ringtone start and stop in the "Start Time" and "Stop Time" columns. Check the two small boxes next to the columns to activate and click the "OK" button to save the changes.
Go to "Advanced" in the menu bar, scroll down the list of options, and click "Create AAC Version." The song you chose to add as an MP3 will now be copied into your iTunes library, but this version will only be as long as the time you specified in the "Start Time" and "Stop Time" columns.
Drag the new track file from iTunes to your desktop and wait for it to copy. Change the file extension name (last three characters of the file name) from "m4a" to "m4r." Click "Confirm" when prompted to accept the changes.
Delete the version of the MP3 initially created. This will still be in the iTunes folder. The only version that you will use now is the one you saved to the computer's desktop.
Drag the song file from the desktop to the left-hand side of the iTunes window and drop it into the media library.
Click on the "Ringtone" file in the left column of your iTunes window. This file appears after the creation of your first ringtone. In the file you can view your newly-created ringtone in the list.
Plug your iPhone into your computer and when iTunes syncs with the iPhone, the new ringtone will be set in the device.