TrafficMonitor - TrafficMonitor is a network monitoring suspension window software in Windows.
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
NetBalancer - NetBalancer is a Windows application for local network traffic control and monitoring.
NetMonster - NetMonster is a networking app by Michal Mrocek that comes up with features to enable you to get detailed information about your current network right on your mobile phone screen.
NetTraffic - Essential network bandwidth monitor.
Ettercap - Ettercap is a suite for man in the middle attacks on LAN.