I have never really been the guy that has custom ringtones for people, but this just makes it too easy. PhoneZoo is a site that is structured a bit like a social network, but you can take ringtones uploaded by other users and send them directly to your phone.
Like I said, it is set up a bit like a social network, in that you can set a status and have friends and what not, but I haven’t seen a reason to utilize these functions as I have enough social networks. However, I am really liking the free ringtones. You can also make custom ringtones from your voice or sound files on your computer.