I phrased the question How do I take MP3 files off an audio CD because people may be asking the question in that form. However, the process is called ripping a CD. To make mp3 files from an audio CD follow these steps:

Follow up:

1 - Insert the audio CD into the computer.

2 - Open Windows Media Player

3 - Click the rip tab

Once the files are all ripped you can find them in your music folder or in the Windows Media Player library. Now you can play your music on your computer while keeping your CDs preserved.

If you want to do the reverse effect: To burn mp3 files onto a CD, then you must burn the CD as an audio CD if it is going to be played in a CD player. If the player is mp3 compatible, then you can hold more music. If the player can play mp3 files, the CD can be burnt as a data CD.