music massage
Archives of a newsletter devoted to mods, with reviews and downloads.
http://www.scene.cz/massage/

Best trackers for making MODs
Reviews on a few tracker programs.
http://www.deltaz-palaze.de/site_tra_info.html

Maz Sound
Large collection of MOD/S3M/XM/IT Tracking software
http://www.maz-sound.com/

DUMP
Short for Denna Urtrista Module Player, this program is a MOD player for Atari Falcon.
http://dump.atari.org/

Graoumf Tracker 2
Graoumf Tracker 2 is an advanced soundtracker with audio fx for Windows 9x/NT/2k.
http://www.sonicspot.com/graoumftracker/graoumftracker.html

Sound Club
Demo is only a player, registered version also serves as a tracker.
http://www.bluemoon.ee/history/scdos/index.html

Winamp
The popular MP3 player can play MODs as well.
http://www.winamp.com

XMP
Extended Module Player for Win95.
http://xmp.sourceforge.net/

Flatdisk Mod Archive
Over 5600 collected mod, xm, it, and s3m files, along with a dictionary of "modspeak".
http://flatdisk.back2roots.org/

MODPlug Plug-In
Browser plug-in version of Olivier Lapicque's MODPlug Player
http://www.modplug.com/

The Official Impulse Tracker Page
Impulse Tracker has an interface very similar to Scream Tracker 3, but includes more advanced features.
http://www.users.on.net/~jtlim/ImpulseTracker/