Greenpeace released its latest listing of information technology companies ranked by eco-friendliness today, promoting it at GigaOm’s annual Green:Net conference in San Francisco. The big winner is Cisco Systems, which topped the Cool IT LeaderBoard, buoyed by its relatively new environmental policies.

To produce the list, Greenpeace looked at companies’ full environmental footprints and at their various initiatives to lessen their impact on the environment and become more energy- and resource-efficient.

Cisco, which knocked IBM out of the No. 1 slot, scored extra points with its push into Smart Grid and connectivity technology, helping not only itself but many other businesses become more energy efficient. Cisco itself has a goal to reduce its emissions by 25 percent by 2012 (from 2007 levels).

The other notable placement was Google, which was dropped to the middle of the pack despite its trumpeting of green efforts and recent approval to buy and sell wholesale energy. The company claims that it wants this capability in order to use more solar and wind generated electricity, but this remains to be seen. Greenpeace dinged it because it hasn’t been as transparent in its emissions reporting. It is also not very forthcoming about the amount of energy being sucked up by its data centers.

Ericsson came in second place, acknowledged for its efforts to measure carbon emissions and other metrics. It equips its customers with the tools they need to see how big their footprints are, and to take action to reduce their energy demands and carbon output. IBM fell to third despite its increased involvement with Smart Grid technology.

The bottom of the list belonged to large electronics manufacturers, including Toshiba, Sharp and Panasonic. While these companies have been racing each other to advanced battery and storage technology that could one day vastly improve the capabilities of the Smart Grid, they have remained relatively quiet about current efforts to shrink their footprints.

Greenpeace was pretty unforgiving in its analysis. As the New York Times points out, Sony is the largest buyer of renewable energy in Japan, but it still came in second to last place because it has not disclosed any emissions data.