Can't be done automatically by iTunes. Basically I've been importing my CD collection into Apple Lossless. My car stereo plays MP3 CDs so I figure I'd make an ultimate mix CD to play in my truck.
So I create a playlist, add the tracks I want into it, select burn MP3 CD in advanced prefs and click burn CD. iTunes errors out stating MP3 CDs can only be created with MP3 files. That right there deserves one big,
WTF?
Why didn't Apple design iTunes to convert non-MP3 files to MP3 files to burn to a MP3 CD. Another restriction placed by the music companies?
After googling around I found this round-about way to create an MP3 from other formats. It isn't pretty but it looks like it may work.
http://www.macosxhints.com/article.p...itunes+aac+mp3
Given a selection of AAC files that you want to burn to an MP3 CD, set your import prefs to MP3 with your choice of bitrate, etc.
Select your tunes in the library or other playlists and batch convert from the Advanced menu -> Convert Selection to MP3
Create a smart playlist named MP3 CD with the only criteria as 'date added is today's date.' Now all of the songs you just converted to MP3 will show up. Note: you may want to also add 'kind is MP3' if you import new CDs to AAC on a daily basis.
Burn your MP3 cd with this smart playlist.
When finished, select all the songs in the smart playlist, hold the option key and hit the 'delete' key. You will be prompted to remove the selected tracks from your Library. Now the dupes you just created are gone ... and your smart playlist will empty, too.