Open Energy Monitor
2009 June 1
From the original website:
This is a project to develop and build a free and open source energy monitor. Energy monitoring is a key technology in building a bright and smart sustainable future. An Energy monitor is a device that enables you to look at your energy use in detail, which appliances use the most energy and when they use it. This makes using energy more efficiently easier.
Definitely a cool initiative and I would love seeing more projects like this one.
another similar site by berkeley guys http://smote.cs.berkeley.edu:8000/tracenv/wiki/acme