Bandwidth Check

I need to check the bandwidth currently being used on my computer. What i am doing is creating something that will relay requests for my webpage throughout my 7 dedicated servers. All i need to do is check what percentage of a computers bandwidth is being used, like on the Task Manager for XP. Is there a control that monitors all of this for you?

I need to have this answer ASAP because my company is setting up 10 dedicated windows servers and i need to make a relay program in the next 3 hrs.

try searching the API docs; there's bound to be something there.