Netmon 3 - Nmcap.exe

Network monitor 3.0 has a command line tool as well to capture traffic. You can use the ‘Nmcap.exe’ tool to capture frames without the GUI. This tool is available in the Network Monitor 3 installation directory.

I'm looking for a way now to intercept the traffic on real time - like breakpoints on fiddler

more info can be found here: http://blogs.technet.com/netmon/

and here: http://blogs.msdn.com/anmolm/archive/2007/02/18/security-tools-for-testers-part-ii.aspx