iTraffic Monitor is a free network monitor and reporting tool that provides a real time graph of network traffic. It provides detailed stats on daily/weekly/monthly/yearly basis. Using this free application, you can easily keep track of your network activity as well as your bandwidth usage.

Networx is a free network monitoring tool that can be used to monitor incoming and outgoing traffic on selected network adapters and connections. You can monitor all your network connections or only selected ones.