Raspberry Pi Electricity Monitor
Update: Maplin have discontinued the electricity monitor used here.
Software for monitoring the electricity consumption of a home with a Raspberry Pi
Full write up: unop.uk/dev/raspberry-pi-electricity-monitor
www folder to
/var for httpd to host and the python file to anywhere.
apt and plug in the receiver.
To run execute
sudo python raspberry-pi-electricity-monitor.py & or add this to
/etc/rc.local to run at boot.
Visit your pi in a browser to see the data.
See also this alternative.