Try this…
In itunes go to edit/preferences/import (the new itunes changed this around a little so look for the import options regardless of which itunes version you have)
Change the import default from aac to mp3.
Then organize your music in itunes according to format by adding the column called kind (right click where it says artist, song, album, genre, etc and click the box called kind)
Click this column.
Highlight all the unprotected aac songs. Right click and click convert mp3.
For the protected or purchased aac songs burn them to a music cd and reimport the songs. Also since you changed the import default to mp3 all the new songs you download will import as mp3 files.
Now all your songs should be mp3 format and usable on any program or any other mp3 player.
(you will have duplicates of your songs in both formats and since ipods also use mp3s you might just want to delete the aac songs)
