The Scene Portal - The Music Scene 

Modules are digital music files, made up of a set of samples (the instruments) and sequencing information, telling a mod player when to play which sample on which track at what pitch, optionally performing an effect like vibrato, for example. Thus mods are different from pure sample files such as WAV or AU, which contain no sequencing information, and MIDI files, which do not include any custom samples/instruments. Mods are extremely popular in the demo world and offer a way of making music of an acceptable level of quality rather cheaply. With the advent of high-quality sound hardware, new generations of mods may even rise to a sound quality nearing that of professional equipment.
Text taken from 'FREQUENTLY ASKED QUESTIONS (FAQ) LIST FOR ALT.BINARIES.SOUNDS.MODS'

No Error - The Scene Music News (reviews and goodies too)
Nectarine - Nectarine is the first demoscene radio broadcasting every days some of the best songs done by sceners since 1988
Maz Sound Tools A large site that includes reviews of trackers, players, encoders as well as CD and soundcard tools
United Trackers We are a non-profit Internet Organization of Music Software Developers, Music Lovers, and Musicians, contributing to the Internet Music Scene with their tracked work in MOD, MTM, S3M, ULT, XM, IT, and related formats

  The Music Scene - Archives and Resources

    ModPlug Central - Our goal at MODPlug.com is to provide newcomers with the information that they need to enjoy the Free Music Scene, as well as provide veterans of the scene with Resources and information to help them expand their horizons
    Trax In Space - The music search e-shop site
    Chip Music Archive
    Chip Tune - Over 2000 individually selected chiptunes
    The Scene United - MP3, MODS, Buzz and Archives
    Hornet - Music reviews and disks from 1992 to 1998

  The Music Scene - Reviews/Magazines

    goodstuff (the scenemusic guide) - this site is dedicated to quality music, made by musicians from the demoscene. our staff reviews only quality tunes which are, from our point of view, something really special you should not miss to listen to.
    Music Massage - independent module reviews
    Csound Magazine

  The Music Scene - Groups

    Abnoral Music
    Brainshakaz - the idea behind brainshakaz is to release some wicked drum&bass and breakbeat vibes on 12" vinyl
    CBR - cbr spreads digital music in mod and mp3 format since 1995
    D-cibel - design the noise
    Electronic Music Productions
    Exogenic Records - Exogenic records was founded in 1996 to release electronic music by Finnish artists
    Five Musicians
    Force Ten - Much as changed since our humble beginnings but one thing didn't: we're still making music, we're still around
    Fusion Music Crew - Where Art Meets Perfection
    Harmful Konektion - Tracked D'n'B/Tekkno 2 your earz ..
    Hellven - Digital music group
    Immortal Coil - A tribute webpage
    Injection Squad - Ready to rock the music scene!
    J'ecoute - return of the cool
    Konsumer
    Kosmic - Is an international not-for-profit organization dedicated to providing free access to original music on the Net, and exploring new ways of distributing artistic creations to the widest possible audience
    Kyoto Republik - To love is to suffer, to be loved is to cause suffering
    Language Lab
    Level-D RecordsMusic is the blood of life..
    Logic Music - Electronic music by the scene
    low.frequency.neenjas - Norwegain Elektronikz
    Miasmah - Chillout with Miasmah
    Milk - Internet module and music label
    Mono Sound Laboratories
    Moplayaz - The styles we prefer are d&b, jungle, sci-fi jazz, dub and trip-hiphop
    Mute2k
    Nash Meja - Home of experimentations
    Noise - New Objectives In Sound Exploration
    Park Allstars - take a walk in the park and enjoy our little reign of melody and coziness
    Phluid - From the remnants of the ACiD music division, Pinion initiates a group on the cutting edge of technology to create and deliver high quality music over the Internet
    Phobic Music Productions - The home of the underground music group called Phobic. Est. 1996 and has released in a steady flow since that time. Quality before Quantity
    PLF Productions - poffelipoff music anno: 1997-20xx
    quikphix records - Free experimental electronic music
    Reaktio Records - techno evolution from detroit to helsinki - humanitarian techno
    Real Smokers - Free quality music
    Rebound
    Setup
    SCP World HeadQuarters - A speedcore/terror/industrial tracker group..
    Superstars
    Tequila - Recycled oldskool
    Tetris - Iis a techno label based on core players but guest releases are warmly welcome
    TheKool Kommunity
    Theralite - We are a collective of musicians that intensively use computers to create electronic music in a wide range of styles
    Tokyo Dawn Recordings - Is an idealistic, non-profit-orientated, friendship-based group dedicated to serving the underground with high quality drum'n'bass/triphop music
    Tokaimura State - we like to walk in wet streets without shoes, wearing the headphones, eat tomatos and feel the nostalgia
    Tranzite
    Ultra Beat - Free original psychedelic trance
    Vivid - Electronic music, artwork & way of life
    Zaag - zaag is 'saw' in Dutch

  The Music Scene - Personal Pages

    Andromeda - by Morgan Norrestam
    iph's goa/trance - If you like GOA & PSYCHEDELIC TRANCE please visit!
    lrs. - This page contains music, mainly in the genre electronica, made by me. a confused boy. seventeen yrs. ov age.

  The Music Scene - Free Trackers

  The Music Scene - Free Samples

  The Music Scene - Free Players

    ModPlug - The one and only webpage embeded module player
    ModPlug Player - A freeware module player for Win9x/NT/2000 based on the popular ModPlug
    Open CubicPlayer - Open sourced DOS player that supports nearly every module format in existance
    Pulse PLayer - A freeware Win9x/NT/2000 player that supports nearly every module format in existance
    Sonique - A freeware stylish Mpeg, MOD, XM, IT, S3M, WAV, CD Win9x/NT/2000 player
    XMPlay - XMPlay is a Windows 9x/NT music player, supporting the MO3, XM, IT, MOD, S3M, MTM formats