From MoonBeam Development:
Ringtone Editor for Android allows you to create ringtones from files you download or put on your phone. Record ringtones from any source you can hear, save them directly to your phone. It provides advanced editing feature lets you delete out anything you don't want in the ringtone. You can share your ringtones and music files to your friends over bluetooth or email. You can assign ringtones to contacts and system events.