For any audio file that is copy-protected (for instance, if you can't play them in WinAmp or if they use a proprietary file format), then you can always stream them to a wav file using the software named Total Recorder, then encode that resulting wav file into MP3 or WMA or whatever you want.

There will be a generational quality loss resulting from data-compressing the same audio stream twice. However, for spoken-word books, this shouldn't be a large issue.

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Tony Fabris