What exactly do you need to clock for? It would make a difference on how you implement the clock. However, for clock synchronization your idea isn''t bad, except that it will be off by the ping time. When you stamp the packet to send to the server, record a value and store that value with the current time on the client. When the server sends the time packet, also have it record the value. When the packet arrives the client can examine the packet for the original time it was sent and subtract out half the trip time, for a more accurate synchronization.

Have you checked out http://www.codewhore.com/
He takes you through an implementation of NTP which achives synchonization within 5ms of the server and client. It''s not too difficult to impelement. Once you achive synchonization, you can pass time critical information between the server and client, as they both have nearly identical clocks, used in dead reckoning, or any other predicitive code. Definetly check out his links sections of good article on designing your network architecture as to minimize latency.

Good Luck.

-ddn