Personally I had the ancient dusty Warcraft 3 CD still laying around, so I just dug that up and used the CD Key to claim it to a modern Battle.net account which gives access to the Warcraft 3 and Warcraft 3 Frozen Throne downloads:
The same way, use a CD Key and download Frozen Throne from the same Blizzard site is what I did, it comes as an installer and works great. Still a fair amount of users play battlenet games too, which is fun.
Just download the WC3 map that you want to play and put it into the map folder, if you host a game now you can find the map in the menu. Warcraft 3 Dota Maps: The biggest map category of all Warcraft 3 maps with an incredible fanbase is by far the Dota map. The creators with the well known main developer Icefrog made it happen, that Dota is like a standalone game inside another game. Dota and Warcraft 3 always seemed to be different things, because Dota is so big. Warcraft 3 Dota has many different types like Allstar maps, Ai (Bot-Versions), RGC maps, LoD maps, and more. Find all Dota Maps here.
Warcraft 3 Anime Maps: Because Warcraft 3 has so many anime and manga fans, a lot of very cool anime Warcraft 3 maps have been created. The special thing with the anime maps is, that the map developers often, render and design the full 3D character models of the anime heroes. This makes the maps bigger to download, but they look really awesome!
Warcraft III: The Frozen Throne adds a host of new features to the game, including four new campaigns that take you across the frozen continent of Northrend. Explore new maps and master new units such as the Troll Bat Riders, the Blood Elf Spell Breakers, and the destructive Mountain Giants.
Undead Web upgrade cost increased to 150/150 from 75/75. Spirit Touch now restores 3 mana per casting, down from 4. Possession has been reworked. It is now a channelled spell with a 4 1/2 second casting duration. During this time, the target is disabled and frozen into place, but is also invulnerable; and the Banshee takes triple damage from all attacks. Stunning or killing the Banshee that is casting Possession will cause the spell to abort. Additionally, the range of Possession has been increased to 350 from 200. Anti-magic Shell has been redesigned. The spell now absorbs the first 350 points of spell or magic damage dealt to the target, but does not grant magic immunity. Note that spells absorbed by AMS can still deal secondary effects, such as stun, paralysis, or mana drain. Also the mana cost of AMS has been re-balanced to 150.
Not so much a full mod as an individual map, but zB Master for Warcraft III: Frozen Throne has been released. It's part of a larger project called Warcraft vs Starcraft, a mod which will attempt to pull Starcraft's elements of play into Warcraft III. This map is only an 8mb download, which you can grab here. 2b1af7f3a8