MP3 stands for MPEG1 (or MPEG2) Audio Layer III. Too often people refer MP3 as MPEG3, which is incorrect, because such format doesn't even exist.
MP3 is a popular compression format used for audio files on computers and portable devices. It is a method to store good quality audio into small files by using psychoacoustics in order to get rid of the data from the audio that most of the humans can't hear.
MP3's bitrates vary from 8kbps to 320kbps. A typical MP3 file encoded at 128kbps is near CD quality. MP3 audio is increasingly being used in video production coupled with various MPEG4 video codecs like divx. View DVD to MP3 Ripper and MP3 to DVD Burner.
MP3 ID3 Tag An MP3 ID3 Tag is information stored at the end of an MP3 file. The tag can contain information about the Title/Songname, Artist, Album, Year, Comment, and Genre in version 1 and also Track in version 1.1. A proposed Version 2 is out which would be extendable to include more information and pictures.