MP3 -- short for MPEG Layer 3 -- is a file format that compresses audio for storage on a computer. Each MB of data in a .mp3 file equals one minute of music or several minutes for spoken word/audiobooks. Because the files are small, they can be easily distributed via the Internet or on CDs and Zip disks. MP3 files can be played from PCs, Palm-sized computers, and dedicated hardware such as the popular Diamond Rio. Using MP3 is legal if the copyright...