Open iTunes.
Create a new Playlist.
Drag the protected AAC files you want to convert to WAV files into the newly created Playlist.
Insert a blank CD-R.
Press the "Burn Disc" icon located in the bottom right-hand corner of the interface to begin burning the Playlist contents to the CD.
Click the CD icon located under the "Devices" tab in the toolbar on the left side of your screen.
Press "Import Settings..." on the bottom right side of the screen.
Open the "Import Using" drop-down menu and select "WAV Encoder." Press "OK" to apply new settings.
Click the "Import CD" icon on the bottom right side of the screen. After the CD is imported, all the songs from your CD should appear in your music library as WAV files.