I made a mistake once by selecting "Manually transfer blah blah blah"....
I couldn't get my ringtones onto the phone.
Then I tried dragging the ringtones directly into the iPhone's ringtone
folder... it got in.... but any additional ringtones added will erase the
first one. heheheh..
Then i realised my mistake.... and unclick the "Manually transfer....",
then it was smooth sailing all the way. By the way, managed to make
ringtones up to 40seconds. Really difficult to make a cut within such
a short frame time.

1. Add the mp3 into iTunes.
2. Right click on mp3 and select "Get Info".
3. Select "Options" tab and adjust the time u want the song to start n stop, all within 40sec. Then press OK.
4. Then right click and select "Convert Selection to AAC".
5. After a new file has been created, go back to step 2 and unclick the 'start' and 'stop' options, then press OK.
6. Drag the new file out to your desktop. And delete the file in iTunes.
7. Change the filetype of the new file on the desktop from .m4a to .m4r
8. Doubleclick the newly named .m4r file and it will automatically be added onto your iTunes' ringtone folder.
9. Then just sync with your iPhone lor......

Anymore problem ah?