ActionTrip.com
   [8.5/10] Reviewed by Uros Jojic. "For all intents and purposes, this is a very solid expansion pack." Also includes screenshots and user comments.
   http://www.actiontrip.com/reviews/medievaltotalwarvikinginvasion.phtml

Hellenic Total War
   Hellenic mod offers new campaign and battle maps, techtree, units including: Spartan Hoplites, Macedonian Cavalry, Persian Immortals and 14 new factions of ancient Greece: Athenians, Persians, Spartans...
   http://www.hellenictotalwar.com

KekvitMod
   Futures playable Irish and Scottish factions, new units, province changes and other improvements.
   http://www.kekvitirae.com/KekvitMod/

Medieval: Total War Viking Invasion
   Official site. Includes forum, information, downloads, and screenshots.
   http://www.totalwar.com/community/viking.htm

The Lordz Site - Mods for the Total War Series
   Offers Napoleonic mod featuring more than 75 new units, mobile artillery, warships, techtree, buildings, flags, banners, portrait images, game pieces, battle formations etc.
   http://www.thelordz.co.uk/

Wes Whitaker's Total Modification Site
   Medmod mod offers new graphics, rebalances units and buildings and introduces new concepts into game like standard and compound bows.
   http://wes.apolyton.net/