An Internet Protocol Network Telephony (IPNT) system has Internet-connected managing computers at plural call centers connected to local agent stations at each call center. The managing computers are adapted to receive IPNT calls from clients at internal routing points. A router coupled to each of the managing computers at the call centers is adapted to execute routing rules to select agent stations for transferring calls received at the routing points, and the agent stations selected can be at any of the call centers involved. In one aspect the router, having selected an agent station at a call center remote from the call center where a call to be routed is first received, requests a routing point address at the remote call center, then transfers the call to that new routing point. The second call center then further routes the transferred call to the final agent station. Statistics may be used in routing, and data regarding client-callers may be routed to the same agent station for display to which calls are routed.