Socket Server Load

I am looking to write a socket server in PHP based on the one here on Kirupa to be used as a game server. I was just wondering if anyone knows what sort of resources such a server might use. I am wondering about memory use per client and CPU usage per client. I have a 192MB VPS, can anoyone hazard a guess as to how many concurrent connections I might be able to have without overloading my server?

I am aware that it would probably be a more efficient idea to write the server in C but I also stand a greater chance of writing a vunerable server that way.

Leo Kent