We have added a new data transfer reporting page. It show data transfer usage for each server for the last 50-odd days. With a summary for this and last month.
At the moment this page only shows useful information for your Dallas-based VPS and dedicated servers. Our networking setup in Dallas permits us to watch traffic flows at our router. And do the data transfer reporting there.
At Dallas we have managed to only count data transfer in and out of our network (and include internal traffic). Which enables us to exclude reasonable internal traffic (e.g. between VPSs or dedicated servers inside the Dallas network) from your data transfer allocation.
If you have a non-Dallas based server then, for now, you will just get a link to the VPS (where we pull the stats from the VPS host).