OpenLynx 0.1.01 is being released: see http://demo.openlynx.org.

It includes a set of specifications and a metering demo that includes the complete source code.

Here is a related article on open source for building automation systems and the Smart Grid, introducing OpenLynx.

http://www.automatedbuildings.com/news/jan09/articles/openlynx/081229032033openlynx.htm