Stands for "MPEG-1 Audio Layer-3."  It is the most popular compressed audio file format.  An MP3 file is about one tenth the size of the original audio file, but the sound is nearly CD-quality.  Because of their small size and good fidelity, MP3 files have become a popular way to store music files on both computers and portable devices.

To listen to MP3s on your computer, you'll need an MP3 player like Musicmatch (for Windows), Windows Media Player or iTunes (for the Mac).  You can listen to the scripture files on a portable MP3 player, like the Apple iPod or the SonicBlue Rio.