When your PS3 needs to send information to the outside world(like a server) it will do so by sending information through a packet. Assuming the PS3 uses a UDP protocol for communication, you'd record all outgoing and incoming packets to and from the PS3. It might not be possible to read and understand the packets, but if it is, you can implement some sort of filter system. A filter will filter out certain blocks of data from a packet. Sadly, you can't directly hook the PS3's networking APIs, well you probably could but it'd be a lot of work. So do it at a router\modem level. I'm sure there are logs and such in your router that will give you a list of outgoing and incoming traffic.