You're absolutely right - smart meters will be able to "talk" to smart appliances and also manage them. Essentially, both smart meters and smart appliances will have the ability to communicate with each other and Zigbee (http://en.wikipedia.org/wiki/ZigBee) is one of the communications methods that's being looked at.
The energy industry's working with the Government to develop standard communications protocols to make sure meters and appliances can communicate without the need to change the meter every time the comms technology changes or improves.
These standards are expected to be finalised in 2011. Meanwhile, we're only carrying out smart metering trials and it's likely that these meters will have to be replaced once the standards have been finalised and approved.
