What's the ID for a zombie head or a mob head in 1.7? I can't find it.
You'll be looking for "skull". However, the nature of the skull will differ depending on what you're intending to do. Do you mean the item version or the block version?
For the item, /giving a player a zombie head:
/give @p minecraft:skull 1 2
The damage value (2) will determine the type of skull. If you wanted it to be a player head, you would change the damage value to 3 and add a tag called "SkullOwner":
http://www.minecraftforum.net/topic/2114709-the-doom-of-the-doctor/
You'll be looking for "skull". However, the nature of the skull will differ depending on what you're intending to do. Do you mean the item version or the block version?
For the item, /giving a player a zombie head:
The damage value (2) will determine the type of skull. If you wanted it to be a player head, you would change the damage value to 3 and add a tag called "SkullOwner":
/setblocking a zombie skull:
The damage value of the block determines position, and the SkullType will instead determine, as it says, the skull type.
To /setblock a player head, you'd need an extra tag called "ExtraType":
You can find more info on NBT tags for entities/tile entities here: http://minecraft.gamepedia.com/Chunk_format
And NBT tags for items here: http://minecraft.gamepedia.com/Player.dat_format
You can also find a large list of the new IDs, provided by Dinnerbone: http://dinnerbone.com/media/uploads/2013-09/files/28_00-44-23_YfmAkomVI.txt
Minecraft-things: http://skylinerw.com
More Minecraft-things: https://sourceblock.net
Guides for command-related features (eventually moving to Source Block): https://github.com/skylinerw/guides
I primarily hang out in the /r/MinecraftCommands discord, where there's a lot of people that help with commands: https://discord.gg/QAFXFtZ
Their corresponding subreddit: https://www.reddit.com/r/MinecraftCommands/
http://www.minecraftforum.net/topic/2114709-the-doom-of-the-doctor/