Modifications and Add-Ons

Battle Tanks
The custom map "Battle Tanks" is offered with information, screen shots, a ladder and discussion forum.
http://btanks.net/

Epic War
Features custom maps for Warcraft 3 Reign of Chaos and The Frozen Throne expansion.
http://www.epicwar.com/

Hive Workshop
Includes map making tutorials and discussion forums.
http://www.hiveworkshop.com/

JASS Manual
Unofficial manual for the JASS scripting language. Includes downloads and news.
http://jass.sourceforge.net/doc/

The JASS Vault
Discussion forum provides advanced JASS help including scripts for triggers, tutorials, and articles.
http://www.wc3jass.com/

Masters of Map Making
Map database, FAQ, forums, and tutorials.
http://momm.seiken.co.uk

Narutowars
Custom map, featuring characters from Naruto. Includes a guide, forum and mission list.
http://www.narutowars.org

Warcraft 3 Hoard
Includes maps, editing FAQs, and links.
http://www.elilz.com/

Warcraft III World Editor Tutorials
Offers tutorials on map making including information on creating triggers, variables and arrays, leaderboards, and loading screens. Also includes a moderated help forum.
http://world-editor-tutorials.thehelper.net/

Wc3Banlist
Program created to control who can enter custom games by utilizing ban lists on the hosted computer. News, FAQ, forum, and download.
http://www.wc3banlist.de/