clip on units already available
The manufacturers magnetic attachments that can go on the meters and capture the LED pulses that the meters give out every x units of energy. These attachments can also 'talk' to the meter to obtain information such as units used etc.
It would not take much to extend these to send this information to the 'internet' so that your smart phone can read it.
The manufacturers obviously will not like this as its cheap and they will not get lots of new meters, they will whine about security of the meters, though this simple comms is not using security.
Note that payg gas meters already have a clip on unit that does this and communicates with a smart card to limit gas and display information.