iTunes 9.1 and forward changed the way it handles song conversions. I’m not quite sure why but Apple made it so converting a song to a different format is no longer just a matter of right-clicking and converting. Instead, with iTunes you’ll have to make an adjustment in iTunes Preferences first.
First, select the conversion format in iTunes:
* Open iTunes Preferences
* Click on “Import Settings”
* Choose the format you want to convert to by using the ‘Import Using’ menu: AAC, AIFF, Apple Lossless Encoder (MP4 or M4A), MP3, WAV
* Click ‘OK’
Now when you want to convert any song to the new format:
* Click on the song you want converted in iTunes
* Click on the ‘Advanced’ menu
* Scroll down to ‘Create MP3 Version’ (or whatever format you selected earlier)
iTunes will then convert the song to the format you selected just as it did in any prior version. If you want to make an iPhone ringtone you’ll want to use the Apple Lossless Encoder or AAC and then rename the .m4a file extension to .m4r just as before.