NetLimiter is an ultimate internet traffic control and monitoring tool designed for Win98/Win98 SE, WinME, Win2000 and WinXP. It is a shareware connection limiting application that's well-designed and customizable.
Here are some screenshots to illustrate the features and user interface of this application:
NetGong
Psiphon 3
Speedify
Net Monitor for Employees Professional
Network LookOut Administrator Pro