I'm under the impression that itunes has it's own format as opposed to mp3. Try putting the files in the ipod into the PC and if it's reconized as MP3. If not then ther might not be much you can do for the itune files which are more or less exclusive to itunes.
On the other hand if you do have MP3's and want to use you're ipod to transfer any files to you're PS3, Enable "Disk use mode" on the ipod and then feed it whatever you want to export into the PS3.
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On a side note for further reference i'll mention, if you know it's an MP3 but nothing is understanding the file format, put on extension on the file.
name.mp3 << When naming files anything after the period would autimatically make it the extension.
Doing this on a PC will make the PC open up the file in whatever software is compatible with it. For MP3's it'll be media player or whatever software you have assigned to open run it.