Windows Server 2008 R2 automatically installs the Active Directory Module for Windows PowerShell and Active Directory Administrative Center when you add the Active Directory Domain Services (AD DS) or Active Directory Lightweight Directory Services (AD LDS) role. When you promote the server to an AD DS domain controller or create an AD LDS instance, the system then installs and activates Active Directory Web Services, which is everything you need to manage Active Directory using Windows PowerShell on that computer.
However, administrators often want to manage Active Directory from another computer at a remote location, and you can do so with the Active Directory Module and ADAC, as long as you are running Windows Server 2008 R2 or Windows 7 on the remote computer.
To manage AD DS or AD LDS resources from a computer running Windows Server 2008 R2 that is not an AD DS domain controller and that does not host an AD LDS instance, you must install the Active Directory Module for Windows PowerShell and (optionally) the ADAC module, using the Add Features Wizard, accessible in Server Manager or the Initial Configuration Tasks window. If you prefer, you can also install the features using Windows PowerShell cmdlets or the Servercmd.exe command-line tool.
Install Remote Server Administration Tools with the Add Features Wizard
The Active Directory Module for Windows PowerShell and the ADAC are part of the Remote Server Administration Tools feature, which you can add as a whole or by selecting individual modules. Both modules require you to install the .NET Framework 3.5.1 feature as well, and to install ADAC, you must also install the Active Directory Module for Windows PowerShell and AD DS Snap-Ins and Command-Line Tools features.
Note that your server must be a member of an AD DS domain with at least one Windows Server 2008 R2 domain controller.
Install Remote Server Administration Tools with Windows PowerShell
You can also install individual parts of the Remote Server Administration Tools feature from the Windows PowerShell prompt, using the capabilities provided in the ServerManager module.
More Here
Courtesy:http://technet.microsoft.com/en-us/magazine/gg413289.aspx