You can still make your own ringtones with the new iTunes 10 and sync with your iPhone by just reading the step-by-step tutorial below.

Requirements :

• iPhone.
• iTunes 10
• A song or audio file in iTunes music library
  
  
  

• Go to Music in your library.
• Right click on your audio file.
• Clic on Get some information then go to Options.
• Determine a sample of 20 to 25 seconds.
• OK.

• Right click on this file.
• Go to "Create an AAC version".
• A new file with the same name but different length is created and is located in your musical library.
• Right click on this file and then display the explorer.
• Copy this file and rename the extension of this file to .mp4r.
• Now go back to your musical library and delete the file created just before.
• On the original file, go to Information >> Options >> Uncheck "Start and End" to have it by default.

Note : For Windows 7, open explorer >> Organise >> Folder Options >> Uncheck "Hide the extension of known files".

• Import in iTunes this new file .mp4r located on your desktop.
• In your device on iTunes, go to Ringtones.
• Be sure that the new ringtone in iTunes is checked.
• Sync.
• Done.