"Active Directory Users and Computers" MMC snap-in for Windows 7?

Question

For Windows Vista and Windows 7 you need to get the Remote Server Administration Tools (RSAT) - the Active Directory Users & Computers Snap-In is included in that pack. Download link: Remote Server Administration Tools for Windows 7.

Per Noalt's answer is correct. However, if you want the snap-in mentioned in the title (Users and Computers), you'll also have to run these commands at a command-line afterwards, as an Administrator:

dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS-SnapIns

Note - I had to run these in order for AD Users and Computers to show up, as they were disabled on my computer after the install. This might not be the case for all users.

I'm not allowed to use Turn Windows features on or off, but running all of these commands in an elevated command prompt (Run as Administrator) finally got Active Directory Users and Computers to show up under Administrative Tools on the start menu:

dism /online /enable-feature /featurename:RemoteServerAdministrationTools
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS-SnapIns
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS-AdministrativeCenter
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-DS-NIS
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-LDS
dism /online /enable-feature /featurename:RemoteServerAdministrationTools-Roles-AD-Powershell

I had downloaded and installed the RSAT (Windows 7 Link, Windows Vista Link) before running these commands.

It's quite likely that this is more than you features than you actually need, but at least it's not too few.

RE: enabling features via the command line

Alternatively, you can enable whichever features you're interested in via the Programs and Features control panel

From the download page Per Noalt provided:

Click Start, click Control Panel, and then click Programs.

1. In the Programs and Features area, click Turn Windows features on or off.

2. If you are prompted by User Account Control to enable the Windows Features dialog box to open, click Continue.

3. In the Windows Features dialog box, expand Remote Server Administration Tools.

4. Select the remote management tools that you want to install.

As @CraigHyatt mentioned in one of the comments:

"Control Panel -> Programs and Features -> Turn Windows features on or off -> Remote Server Administration Tools -> AD DS and AD LDS Tools"

This worked like a charm in Windows Server 2008. A reboot was necessary, but the Active Directory Users and Computers snap in was available after that.

I know that this question is old, but it is first in google searches

For the windows 8.1, the tools can be downloaded here
http://support.microsoft.com/kb/2693643

For the windows 10, the tools can be downloaded here
https://www.microsoft.com/en-us/download/details.aspx?id=45520

EDIT: After installing the Windows 10 2015 "Fall Update", I had to reinstall the remote server administration tools.

The commands from WEFX worked for me after I enabled the parent features RemoteServerAdministrationTools, RemoteServerAdministrationTools-Roles, and RemoteServerAdministrationTools-Roles-AD