ngrep stands for network grep. It is an easy to use packet sniffing tool. Versions are available for at least *NIX and Windows NT (and variants).
You can tell it to listen for packets for a certain host and port for and a regular expression for packets to match against. When it finds a matching packet, it dumps the details to standard out.
If your network administrators are particularly stupid then they will have set up the network with simple repeaters rather than switches; this, combined with the fact that everyone has to log in using their domain credentials in clear text to an Igear server before using the Internet means that you can very easily compile a list of everyone's usernames and passwords for amusement/blackmail.