Video codecs:
DivX Codec - http://www.divx.com/divx/?src=toptab_divx_from_/index.php
FFDSHOW - http://sourceforge.net/projects/ffdshow
XviD - http://www.xvid.org/

Video players :
AC3Filter - http://sourceforge.net/projects/ac3filter
BsPlayer - http://www.filehippo.com/download_bsplayer/
Crystal Player - http://www.crystalplayer.com/index.php?page=downloads
Cygwin MPlayer - http://armory.nicewarrior.org/projects/cygmp/
DivX Player - http://www.divx.com/
MaximusDVD - http://www.maximusdvd.com/
Media Player Classic - http://sourceforge.net/project/showfiles.php?group_id=82303
VideoLan - http://www.videolan.org/

Video tools:
DScaler - http://deinterlace.sourceforge.net/
FlasKMPEG - http://www.flaskmpeg.net
GSpot - http://www.headbands.com/gspot/
TMPGEnc - http://www.tmpgenc.net/e_main.html
VCDEasy - http://www.aplusfreeware.com/categories/Audio-Video/VCDEasy.html
VirtualDub - http://www.virtualdub.org/
VirtualDubMod - http://sourceforge.net/project/showfiles.php?group_id=65889
Zwei-Stein Video Editor - http://www.thugsatbay.com/software/index.html