I've been trying to do this myself, but I don't have a lot of time. I tried iPhoneConnector 0.2.0 and I couldn't do anything with it except look at some files. I'm itching to put my own ringtones on my iPhone.
EDIT: There are two ways I _THINK_ it can be done:
1) With a serial connection tool
2) A modified DMG file, and then "restored" to the iPhone using iTunes.
I don't know which method was used.