A simple listing of Witch Doctor skills, as seen on the Blizzard site and observed in the WWI gameplay movie.
Firebomb
This skill allows the WD to lob blazing projectiles, like molotov cocktails, at his enemies. They may be thrown varying distances, from most of the way across the screen to nearly at the WD's feet. The burning bottle tumbles end over end in mid-air, and explodes with a burst of flame when it lands, dealing fire damage and knocking back anything in the immediate vicinity. The spell seems to involve some sort of fire spirit, not just a flammable substance, since a flaming figure is briefly visible overhead when the firebomb bursts. It also sets targets aflame, and they take continued damage from the fire for several seconds. There are fires left burning on the ground after a firebomb detonates, but these do not seem to deal damage to, or set fire to, targets that walk through them.
Horrify
This curse-like spell works like the terror curse (or the barbarian's grim ward skill), but functions almost like a terror aura; causing any monster near the WD to flee in fright. Monsters in range are overcome with fright and immediately scatter, running away from the WD. The skill works by summoning a frightening spirit, which appears above the WD and screams and shakes its arms at the monsters. Presumably, any monsters that come into range while the horrify spirit is active are affected by it, essentially making the WD a moving object of terror. This limits the skill as well, since it can't be cast on individual targets, or cast a great distance from the WD.
There look to be 2 durations; how long each individual fright lasts on afflicted monsters, and how long the frightening spirit remains over the WD's head, capable of horrifying or re-horrifying anything that comes into range.
Locust Swarm
This projectile emits a spray of green insects which swarm over anything in close range, like flying piranha. Each swarm seems to last for a given amount of time, and if they kill one monster and still have some duration remaining, they will spread to others. They gain time by consuming each target though, and in a mob the locust swarm can act in chain lightning fashion, leaping from one enemy to another, killing a dozen or more targets if they are closely spaced.
The locusts can also be sprayed on the WD's minions, where they will ride along, without hurting the minions, and grant poison damage to the minion's attacks.
Mass Confusion
This curse-like mind control attack summons a blue spirit wherever the WD targets it. The spirit confuses some of the monsters in range, causing a aqua light to appear over their heads. Confused monsters seem to lose their AI, and they mill around more than usual. They may also attack, or be attacked by, other monsters. They are not the WD's minions though, and are not under his control, so he can kill confused monsters just like any other monster.
Soul Harvest
This skill creates a nova-like ring of blue smoke around the WD. All targets within the ring are damage, and if the damage is enough to kill them, their souls (white/blue ghosts) swirl into the air, then down into the witch doctor, where they presumably add to his mana or life. The radius of the skill is not very large, so monsters need to be nearly in melee range to be affected.
Zombie Wall
This skill works much like the Necromancer's bone wall; causing a straight line of obstacles to erupt from the earth. Not merely obstacles though, this wall is made of zombified creatures who claw at and deal damage to any monsters who come into range. Monsters attack the wall, so this isn't hard to do.
The wall zombies are very powerful in the WWI gameplay movie, ripping every monster to shreds in seconds, but it's assumed the skill is high level, or the character has a lot of points in it, since it looks overpowered. The wall will theoretically serve a defensive purpose as well; blocking shots from ranged attackers. It's not known if it can stop the advance of larger monsters, who might just step over it or crush it.
Summon Mongrel
The Witch Doctor summons a mangy zombie dog which attacks the target like one of the D2 Druid's wolves. Mongrels can be detonated in a Corpse Explosion like attack, dealing heavy damage to any nearby targets.