BitMeter OS is a bandwidth meter. It logs how much data is uploaded and downloaded from your system and records this information in an SQLite database. The database can be queried from the command-line or monitored in real time.
The Deimos Project is a computer statistics/monitoring tool allowing you to gather information and statistics about your computers, including network information and bandwidth, uptime information, keyboard and mouse usage, and hardware information.
IFMon (Interface Monitor) displays the traffic, state, connection, and other information of a network interface as a small console window. The information for the network interface being monitored is obtained from the files in /proc to help simplify portability.
NetsGraph is a simple PHP class to generate statistical graphics from network data transfers. It accepts as input a list of samples representing the average network data transfer on a specified interval and is able to create native SVG graphics or PNG images.