An article on stuff presents a device made by Current Cost that monitors energy consumption in real time and sends data usage to Google Power Meter.

A user though has to keep a computer running all the time in order to collect data wirelessly from the device and update it to Google.
Through Powershop, that is also possible today. I've personally spent a few nights working with Powershop's developer API and managed so far to collect data from Powershop and then send it to Google.
Check this thread out: http://groups.google.com/group/powershop-developers/browse_thread/thread/54460039ec71fa1b
My aim is to develop a Google App Engine application that could collect that for me at a set interval.
Powershop's Ari Sargent has also experimented with Google Powermeter and they may provide a link with that tool themselves.
By the way, their web site is excellent and they could provide similar, or better, gadgets.