sharing desktop of workstation

Scenario.

Machine “A” WINNT 4.0 PDC Server being used as an Internet Gateway.

Machine “B” Win98 Workstation connected with NTSERVER (Machine “A”)

Machine “C” Win98 Workstation connected with NTSERVER (Machine “A”)

What I need is a software by which I could share the Desktop of the Workstations such as If a Video CD is being watched on any client machine,I wish to enjoy it with the user of client machine at the same time. Can anybody tell me about such software or a way to acquire this.

Thanks in advance.