While this functionality should soon be available in some sort of cool open source UI package, the folks at HacktheiPhone have broken down the process into 23 easy to follow steps that involve downloading the iPhone restore files, hacking the crap out of them, putting your own ringtone into a folder, and uploading it. I’m going to put on an MP3 of my mom telling me how good I am. And then I’m going to visit the iPhone instead of going to visit her at the retirement center. The iPhone understands me.
How to add a custom ringtone (for intel Mac users only…for now) [HacktheiPhone]