aiff format??? playing in quicktime?????

What are your burning options set in iTunes prefs>Advanced>Burning.

If you have Audio CD selected and burned that way then when you put the CD in the drive the audio files will show aiff and play w/QT. If you want - you can open iTunes and the CD will show in the Source column and you can play the CD in iTunes.

MJ

The way to play an audio CD on a computer is usually NOT to double-click its icon from the Desktop or Finder window. Instead, use System Preferences > CDs & DVDs to set your preference for what OS X should do when you insert audio CDs. You can, for example, set it to open iTunes automatically. Otherwise, you should do as the other poster suggested and open iTunes manually and then play the CD from therewithin.

As far as the issue with AIFF vs. MP3, you definitely have burned yourself an audio CD. There are no files on the CD, but the Finder will recognize each track as an AIFF "file." You can't change the default application associated with tracks on an audio CD. If you have some AIFF files on your hard drive, you can use one of those to change the default file handler to iTunes instead of QuickTime.

If you want to burn MP3 CDs, as was already pointed out, you'll need to change your settings in iTunes > Preferences > Advanced > Burning. Be aware also that all of the source files must be in MP3 format. If they aren't already, you'll have to convert them to MP3 first.