MP3licensing.com  
   Details of the MP3 licensing programs for Thomson Multimedia and Fraunhofer IIS-A.
   http://www.mp3licensing.com/

Fraunhofer IIS: MP3  
   Features history and technical information about the MP3 format.
   http://www.iis.fhg.de/amm/techinf/layer3/

MPEG Audio Frame Header  
   Technical explanation of how MPEG audio files and their headers are constructed.
   http://www.dv.co.yu/mpgscript/mpeghdr.htm

MP3-O-Phono  
   A custom made MP3-player device. Site contains many implementation details as well as photos.
   http://www.softlab.ece.ntua.gr/~sivann/mp3ophono/

MAP - MP3 Audio Player  
   Describes how to build a standalone home stereo MP3 player. The player is DOS-based and built with standard low cost PC-components.
   http://www.geocities.com/jui_m/

ID3v2  
   Description of ID3 tagging standard (version 2) for MP3 files. Includes specifications, implementations and a mailing list.
   http://www.id3.org/

MP3 Tech  
   Source of detailed technical information about audio encoding with MP3 and similar formats. Features documentation, articles, source code and a message board for programmers.
   http://www.mp3-tech.org/

mp3PRO  
   Alternate audio compression format that is both backwards and forwards compatible with MP3 yet with significantly smaller file sizes. Site features articles, downloads and a forum.
   http://www.mp3pro.ws/

MP3Pro Soft  
   Features software and information about mp3PRO and other similar audio formats.
   http://mp3pro-soft.narod.ru/e_index.html