Active Directory Service Interfaces

Active Directory Service Interfaces (ADSI) is a set of COM interfaces used to access the features of directory services from different network providers. ADSI is used in a distributed computing environment to present a single set of directory service interfaces for managing network resources. Administrators and developers can use ADSI services to enumerate and manage the resources in a directory service, no matter which network environment contains the resource.

ADSI enables common administrative tasks, such as adding new users, managing printers, and locating resources in a distributed computing environment.
http://msdn.microsoft.com/en-us/library/windows/desktop/aa772170(v=vs.85).aspx

Active Directory Service Interfaces Reference
http://msdn.microsoft.com/en-us/library/windows/desktop/aa772218(v=vs.85).aspx

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We can use System Providers in ADSI to create object and remotely manage Active Directory.  ADSI includes the service providers listed in this page:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa772235(v=vs.85).aspx


Example:

For ADSI WinNT Provider

We can use Set objUser = GetObject("WinNT://"& strDomain &"/" & strUser) to create an IADsUser object and access the IADsUser object properties.

This page has all the objects of WINNT provider
http://msdn.microsoft.com/en-us/library/windows/desktop/aa772211(v=vs.85).aspx

IADsUser is one of the WINNT objects. This page has the interface of IADsUser, including methods and properties.
http://msdn.microsoft.com/en-us/library/windows/desktop/aa746340(v=vs.85).aspx

This method can set user password: objUser.SetPassword strPassword