Simple upload/download monitor

Hi

As a small project i am looking at designing an upload/download monitor where you can choose which network connection you want the program to monitor and it will keep an up to date value on bytes uploaded and bytes downloaded, i dont want to know what is being uploaded or downloaded, or who by, or where its going etc, just the amount being transfered. Is there an API that you can use to get the uploaded/downloaded amounts? (as shown when you double click on an active connection in the system tray)

Thanks

Arachnid13