How to Convert iTunes Downloaded Music (.M4P) to MP3

1. Create a new playlist for your iTunes library
2. Add all songs downloaded from iTunes that you want converted.
3. Go to "Edit", "Preferences", "Advanced", "Importing", and then change the format in the box- "Import Using..."
4. You may choose the format you would like. (you may choose from AAC, AIFF, Apple Lossless, MP3 or WAV.)
5. Press Ok.
6. Insert a CD of any kind.
7. Once you have all the songs on your playlist, on the Navigation Bar, right click on the playlist and select "Burn Playlist to Disc".
8. Once finished, click on the CD in the "Devices" section.
9. Select all of the songs (click on the first song and then shift+click on the last song), and then right click on the songs and select, "Import Selection to (your format)", or what your version of iTunes says.
10. Locate your songs in your iTunes Library and load album artwork.
11. Find your iTunes folder in your Documents or wherever you set it up to be.
12. In the artist's folder, you should see a new song in the new format.
13. Great job! We just removed the DRM-Protection and changed the format of an iTunes Library song. There was never a need for any other programs.
14. Load and enjoy.

For free downloadable converters here are some to check out:

http://download.cnet.com/Free-M4a-to-MP3-Converter/3000-2140_4-187723.html