Wow I am truly blown away by the responses. Thanks a bunch!
Ephemera: "I have written a daemon for my own amusement."
that's amazing I will be trying this out asap.
J65nko: All of our "regular" traffic goes out an unlimited connection so there is no worry there. We are already running a proxy to filer out ad's and other various crap.
If anyone was wondering, I ran the script s0xxx suggested for a few days and something is messed up with it. Here is the output:
External interface bandwidth usage:
uptime 10 days
ExtIf in total -1 GBytes
ExtIf out total 1 GBytes
ExtIf in/day 0 MBytes/day
ExtIf out/day 0 MBytes/day
ExtIf in/30day 0 GBytes/month
ExtIf out/30day 0 GBytes/month