>>This is a new area to me. Could you recommand some articles or web sites in this area to me.
>
>I don't know good articles on this subject. You can download ADSI White paper from http://www.microsoft.com/windows2000/docs/adinterface.doc MSDN info mainly for C++ developers. Something useful may be found at Platform SDK->Nerworking and Directory Services->Directory Services->ADSI->ADSI Scripting Tutorial. Also take a look on KB articles about using ADSI in VFP written by Mike Stewart.

Alexander,
I don't know how good ADSI will be in this case. The code you described will return all users with an account on the server whether they are connected or not.