RDP in XP domain to remotely mirror multiple-monitor host workstation

Question : What is most efficient method (hardware, software, or combination) to achieve the following objective?
Objective : Mirror in real-time (no noticeable latency to naked eye) a domain user’s Window session on a multiple-monitor XP workstation (PC #1) to a second multiple-monitor XP workstation (PC #2), when both workstations are in the same domain and on the same LAN. By “mirror” we mean having the same domain user’s Window session running simultaneously on both workstations (PC #1 & PC# 2, in this example).
All suggestions welcomed.