Free Ringtones for iOS 7 offers a huge collection of ringtones for iPhone, and includes a function for creating your own tones.

Based upon the Pimp Your Sound app, Free Ringtones for iOS 7 includes a cataloged collection of tones for calls, alerts, messages, etc. There's also a ringtone maker and sound theme maker, where you can produce your own tones. You can do this by editing music from your device or recording sounds.

Free Ringtones for iOS 7 is a great way to customize your iPhone's sounds.