I don't have many but I basically made my own. Took some songs, chopped them down with something (I think movie maker), converted the file type to mp3 or aac and found a website with forums for phones and found the instructions to load them onto the phone there. There are websites that will help you send ringtones to your phone, but I just used ftp.
Certainly there are simpler ways to do this, I just don't know about them.