Use something like <a href="http://www.versiontracker.com/moreinfo.fcgi?id=10417&db=mac" target="_blank">AudioCorder</a> to get the audio into your comptuer, then Toast or iTunes to burn it to a CD.
To maintain the best quality, use 44.1kHz, 16bit stereo. That's the AIFF format used in a standard Red Book audio CD. After you burn the CD, you can then use iTunes to compress the audio to MP3 to listen on your PowerBook.