These instructions refer to iTunes 6.0.4. Earlier versions may function slightly differently.
•On a Macintosh computer, open iTunes.
•You will need an AIFF (or other compatible format) audio file in your iTunes list, either from a CD or from a file on your hard drive.
•Go iTunes>Preferences. In the resulting window, click the Advanced button. In the resulting window, click the Importing tab at the top of the window to open the Importing window.
•Find the Import Using: menu, and select MP3 encoder. Find the Setting: menu, and select Good Quality (or a higher setting if your prefer). Deselect Play songs while importing, check Create file names with track number.
There are several different format options that you could use to convert audio files. For example, you could convert an MP3 file to an AIFF file if you wanted.
•Still in iTunes>Preferences, click the General button. Deselect Copy files to iTunes Music folder when adding to library. Hit OK to close the Preferences window.
In the iTunes window, find the + button in the lower left corner and hit it to create a new Playlist. Type Conversions and hit Return to rename the playlist. Select the playlist in the Source column to show its contents (it will be empty).
•On your Desktop (or whatever its location on your computer) find the icon for the AIFF file you want to convert. Drag it to the Conversions playlist window to add it to your Playlist.
•In the Conversions playlist, click your file to highlight it. Go Advanced>Convert Selection to MP3. The file will be converted. When conversion has finished, quit iTunes.
•Now the hard part: locating your file. Go to your home folder and then go Music>iTunes>iTunes Music. Here is where iTunes stores the music it keeps it its library. Your music is in one of the folders in this window, probably in Unknown Artist.
The easiest way to find the file is to go File>Find and use the Sptolight window search for the file name.
If you want to set a dedicated location for your conversions, open iTunes, then go iTunes>Preferences and click on General. In the resulting window, the box under iTunes Musid folder location shows the current location in which iTunes stores "imported" files. You can change this by hitting the Change button and navigating to a different folder.
•When you have found your converted file, drag it out onto your desktop, or to another location that you choose.
•Your mp3 file is now ready for use. To test it, drag it to the Quicktime icon in your Dock, let it open in Quicktime, and hit the Play button.
If you don't hear anything, check the speaker volume by going to the number pad at the right of your keyboard, and hitting the second button from the left in the top row.