Although you cannot set songs that show up in the iPod app of your iPhone as ringtones, you can convert your songs to a ringtone format iPhone will recognize using the same iTunes software you use to sync your iPhone. When you have properly formatted your song, you can add it to your iPhone and set it as your ringtone.
Select the song you want to set as your iPhone ringtone in the iTunes music library.
Select "Advanced" from the menu bar at the top of your screen. Choose "Create AAC Version." If the format listed is different from AAC, you can adjust it to AAC by selecting "Edit," "Preferences," "Import Settings" from the menu bar and clicking on the first drop-down menu to set it to "AAC Encoder."
Choose "File," "Show in Windows Explorer" from the menu bar to display your file on your hard drive, so you can convert it to ringtone format. Edit the file format by right-clicking on the file and selecting "Rename." Change ".m4a" to ".m4r," which is the format iPhone and iTunes will recognize as a ringtone.
Delete the AAC version of the song you created by returning to iTunes and pressing the "Backspace" or "Delete" key while it is selected. When iTunes prompts you, select the "Keep File" option. This will delete the file from iTunes while retaining your .m4r file on the computer. Click on the .m4r file in Windows Explorer and drag it to the iTunes library. It will show up in the Ringtones library.
Move the ringtone to your iPhone by connecting the device to your computer and dragging the ringtone to the iPhone "Devices" icon from the Ringtones library.
Set the song as your ringtone from the "Custom" list in the "Ringtone" option when you open the Settings application on your iPhone and tap "Sounds."
- You can create a 40-second sample clip from a song you want to use as a ringtone using any song in your iTunes library. Open the "Options" tab in the song information panel, which you can access by selecting "File," "Get Info" from the menu bar. Choose a 40-second part of the song and enter its beginning and end in the "Start Time" and "Stop Time" fields prior to completing Step 2.