Create a ringtone for an iPhone

A quick list of how to create a ringtone for an iPhone. This is more a cheat sheet than an a full walkthrough.

1. Create a less than 30 seconds sound file in a format iTunes recognizes (mp3, aac, etc).
2. Import this file into iTunes.
3. In iTunes, convert the file to AAC.
4. Find the converted file, should be *.m4p.
5. Rename a copy to *.m4r.
6. Import the renamed file into iTunes. It should be listed in "Ringtones".