Open iTunes and click on "Edit" in the command bar. Select "Preferences" from the drop-down menu that appears.
Under the "General" tab select "Import Settings" and pick "Apple Lossless Encoder" as the import method. Click "OK" to close the Preferences menu.
Create a new playlist in iTunes ("Ctrl+N") and drag the desired M4P files into the playlist. If the playlist is greater than 79 minutes long you must create additional playlists, as you'll be burning this list to an 80-minute CD.
Insert a blank CD-R in your CD drive and click on the playlist if it is not already highlighted. A "Burn Disc" button will appear in the bottom right corner of iTunes. Click on that button to burn the M4P files to disc. When iTunes is finished burning the files, the disc will eject from your computer.
Put the CD back in your computer. ITunes will detect the CD and ask if you want to import the CD. Click "Yes." The imported files will be M4As free of the original DRM restrictions.