If you want to customise the sound your iPhone makes when you receive a call, you can create your own ringtones using the music stored in your iPod app. You will need to download a ringtone-making app, but the iTunes App Store offers several of these, and many of them are free as of 2011. Some of the most commonly downloaded ringtone apps include Ringtone Designer, Create Ringtones!, Ringtone Maker, Custom Ringtones and Ringtone Star.
Tap the App Store icon on your iPhone's home screen.
Tap "Search." Tap the search bar. Type "create ringtone." Tap "Search."
Browse the list of available apps. Tap an app to read a preview; tap the back arrow to return to the list.
Tap the app that you want to download. Tap the button with the price, such as "Free." Tap it again when it turns green. Enter your Apple ID and password.
Tap the app on your home screen when the progress bar disappears. Tap the option to create a ringtone from a song; then tap the song you want to use in the list that appears. Use the time-markers to set a 30-second or shorter clip and name your ringtone if necessary. Tap the option to create the ringtone. Set the ringtone when asked by the app or under "Sounds" in the Settings app.