In the Project Chooser, click on "iPhone Ringtone." Ringtone types will be displayed in the right side template area.
 For this article, we'll use the sample ringtone template. In the "New Project from Template" dialog, give your ringtone a name, and where you will save it. You don't need to worry about the tempo or key signature information for this. When ready, click the "Create" button.
 This will turn your sound into a loop.
 Drag either end of the yellow Cycle region so that you've selected only that part of the song you want to become a ringtone. Ringtones can be up to 40 seconds long.Note: you can play the sound, and audition the loop as you make adjustments.
 From the Share menu, select "Send Ringtone to iTunes." iTunes will open.
 Click on the Tones tab, then click on "Sync Tones," and select your new ringtone in the list. When you're ready, click Apply, and your ringtone will be loaded onto your iPhone.
Launch Garage Band.
Double-click a template.
Enable the Cycle button.
Adjust your selection.
Send the ringtone to iTunes.
Sync your iPhone.
{"src": "wikihow-all_validation", "title": "How to Get Ringtones on an iPhone3"}