Here's the correct procedure for making an MP3 out of your finished mix (done in DP or AudioDesk). This FAQ doesn't apply to Performer 6.

1. Make sure you're listening to your mix thru ONE stereo pair like "Out 1 & 2" in sound manager, "Analog 1 & 2" on the 2408, or "Main Out 1 & 2" on the 1224. Make sure MIDI isn't part of the Mix you're listening to (MIDI tracks would have to recorded in as audio).

2. Hit "CMD A" to select all tracks.

3. Choose "Bounce to Disk" from the Audio Menu.

4. Select Split Stereo for "channels", 16 Bit for "resolution", Add to Soundbites Window fror "import" and set your "output source" to match the stereo pair you determined you're using in step one. Also give the file a name. Hit OK and let the file bounce.

5. Find and select the bounced file in the Soundbites Window (Windows Menu>Soundbites).

6. Choose "export selected bites" from the mini menu in the upper left hand corner of soundbites window and select AIFF. Save it to a location you'll remember.

7. Drag the AIFF you made in step 6 into iTunes, and use the "Convert to MP3" option in the Advanced menu. You may have to set immport options to MP3 in iTunes preferences.
If you don't have iTunes, you could use MP3 converter like or Sound Jam, MAC AMP, Etc.