FreeMeter - Monitor network bandwidth (C#.NET 2k/XP+). Desktop and Systray graph.
NetLimiter - NetLimiter is an ultimate Internet traffic control and monitoring tool designed for Windows.
NetSpeedMonitor - NetSpeedMonitor is a lightweight Network Monitoring Toolbar for your Windows Taskbar
TrafficMonitor - TrafficMonitor is a network monitoring suspension window software in Windows.
NetBalancer - NetBalancer is a Windows application for local network traffic control and monitoring.
trafficWatcher - trafficWatcher is a small tool to monitor your network activity.