MSN Messenger Spy for MAC?

Hi guys... I'm new to this site so please forgive me if this has already been discussed. I know there is a program called MSN Monitor or similar that can monitor MSN Messenger conversations on any computer in a network and record them to your computer or email. I have recently switched to MAC from PC and installed MSN Messenger for MAC.
Does anyone know of a similar monitoring program available to download for MAC so that I can record MSN conversations on this computer (mac) and the PC in my network?

Any help would be greatly appreciated... (it's slightly urgent!)
Thanks

Depending how savvy you are with Terminal, you can download software called Dsniff which comes with an msn sniffer. In order to make this work, you need to "Span" the port on the switch that's going to the Internet. Switches won't allow you to sniff all other port traffic, so, this spanning is necessary.