You could create your own:
Creating and buying a ringtone for your iPhone (U.S. iTunes Store)
Introduction
You can create iPhone ringtones from many songs purchased from the iTunes Store on your computer. Personalize your ringtone by choosing up to 30 seconds of your favorite song with the easy-to-use iTunes ringtone editor. You can also fade the ringtone in and out, and choose how long to wait before looping the ringtone.
Created ringtones are only available for purchase from the U.S. iTunes Store on your computer.
Note: Select ringtones are now available for purchase from the iTunes Store on iPhone (running iPhone OS 3.1 or later). Read this article for more information about using the iTunes Store for iPhone.
How To
Here's how to create a new ringtone:
1. From your iTunes Music library, select a song that you've purchased from the iTunes Store.
2. Choose Store > Create Ringtone. If a song is eligible to be created into a custom ringtone, the Ringtone Editor appears at the bottom of the screen. If a song is not eligible, you will see the message: "This song cannot be made into a ringtone."
3. Adjust the highlighted area to choose your preferred segment of the song (up to 30 seconds). You can also fade the ringtone in or out.
4. To change the gap between rings, choose an option from the Looping pop-up menu. Click Preview to hear your ringtone before purchasing. Once you're satisfied with your ringtone, click Buy
5. Once you create a ringtone, sync it to your iPhone. You can have your ringtone play for all phone calls or assign ringtones to specific contacts.
