unpack() and binary data

First of all, I have nearly no idea as to how to interpret binary data. But Im attempting to parse binary data for file metadata information (like mp3 files). Concerning unpack(), I can across this link from the notes in the manual -> http://fooassociates.com/phpfer/html/rn45re877.html This has somewhat made things a little clearer as to how to move around in a binary string. But as a total newbie at this, I was wondering if there are any more examples or tutorials, that would be geared towards my intellectual ablity in this matter. Any tips and or hints would be greatly appreciated. Thanks