Over 2,000 Downloads on MinecraftForums!!!

Zombie apocalypse in Minecraft!!! This mod creates a new experience for Minecraft players while keeping it close to the Minecraft we all know and love!

Information:

Simply Zombies is a mod that turns minecraft into a zombie apocalypse. It doesn't contain any new items or fancy features, keeping it simply and fairly similar to normal minecraft just with the zombie apocalypse twist on it.
Removes all mobs except zombies (zombies can now drop other mobs items, such as gunpowder)
Zombies are now faster, spawn more often, and do not burn in daylight (They also don't spawn more zombies when being attacked)
Zombies will not catch on fire from being in sunlight
Nothing changed in the Nether or End, however endermen will not spawn in the over world (you can still get enderpearls from zombies)

Installation:

Install the appropriate version of Forge for the version of the mod you want to download
Download the version of the Simply Zombies mod you want to install
Extract the zip file you got from downloading the mod
Place the new "SimplyZombies" folder inside the "mods" folder in your minecraft directory
Launch minecraft using the "forge" profile, and you are ready to play!

Available Versions:

1.7.2 (Release) (May Also Work for 1.7.10 - Haven't Tested)
1.6.4 (Release)
1.6.2 (Release)

Enjoy The Mod!

Simply Zombies