1. You need to download and install M4P MP3 Converter.
  2. Open iTunes and select "Authorize Computer..." from the "Store" menu. Enter your username and password and press "Authorize" button.
    Authorize your computer for proper music conversion
  3. Run M4P MP3 Converter.
  4. Add your M4P files to program's batch list by pressing "Add Files..." button, you can also press "Add folder" button and add whole iTunes Music folder:
    Add some M4P files
  5. Select M4P files you just added to batch list and set output folder where your converted MP3 files will be placed:
    Select output folder for MP3 files
    If you want to keep your Artist/Album folder structure you can use output settings like this:
    Select output folder for MP3 files
    You can skip this step if you want to keep converted files in the same folder as your original M4P files.
  6. Press "Start" button to begin conversion process:
    Convert M4P to MP3
  7. Wait for few minutes. That's it. You have just converted your M4P files to MP3.