Unfortunately the procedure is not an easy 1-2-3.
Convert your AAC files to mp3's first.
Go to
b Preferences > Advanced > Importing
and select
b MP3 Encoder
at
b Import Using:
Now select all songs in the playlist you want to burn as mp3 CD and choose
b Convert Selection to MP3
from the
b Advanced
menu in the menubar.
This action will make copies of your songs in mp3 format. Your original AAC files are not modified.
If all your files are AAC it is easy to select your just made mp3's.
Make a New Smart Playlist and set the following rule:
Kind is MPEG audio file
Next set
b Disc Format:
(in Preferences > Advanced > Burning) to
b MP3 CD
and click 'Burn Disc' (top right in your iTunes window)
note: you cannot convert Protected AAC (purchased music) to mp3.
You have to burn them on an
b Audio CD,
re-import them and then convert them to mp3.
Hope this helps.
M