BitMeter OS is a free, open-source, bandwidth monitor that works on Windows, Linux and Mac OSX. BitMeter OS keeps track of how much you use your internet/network connection, and allows you to view this information either via a web browser, or by using the command line tools.

Changelog:
Bug 3166063 fixed (query results incorrect, affected by timezone))
Bug 3176678 fixed (Windows installer can corrupt system path)
Fixed broken XML entities in mobile interface
Disk I/O optimisations
Minor improvements and bug fixes

Program Information Category: Tools and Utilities Type: Free Version: 0.7.3 beta Size: Works on: Windows, Mac, Linux Product page: here