Interesting idea, but I was thinking of getting something that isn't dependent on teh Internets.
Has anyone used one of the real-time home energy monitors - like these?
TED 1001 The Energy Detective | TerraPass: fight global warming, reduce your carbon footprint
Home Energy PowerCost Monitor - free shipping | TerraPass: fight global warming, reduce your carbon footprint
They seem to be a level above the basic Kill-A-Watt.