I have been looking for something like this for a while, and The Press had a little piece about it recently.
It is a little device that measures power consumption of your house and displays it in cents per hour. I have ordered one, so will post a few comments in a month or so. I have always been interested in knowing how much power particular devices use. This device should allow me to do that without too much trouble.
It is billed as a device which will save you money. Of course, the more people reduce their power bills the less pressure the environmentalists in the government will be under to build a load of new coal fire power stations, but you can't have everything.
And while I am on the topic, a reminder of Not PC's post on the reason why power is so expensive: not enough generation!