Not sure which of you are reading this from parts outside the United States (not that it really matters because green tech is a global issue), but just became aware of the European Code of Conduct on Data Centres Energy Efficiency. Yes, I'm using the British English spelling, because it just seems appropriate. I also love the idea of a code of "conduct": It suggests without prescribing, but appeals to the whole honor system thing that is so integral to the green movement.
The document is meant to provide constructive ideas for reducing energy consumption without adding ridiculous extra costs. While I am sure there is some region-specific advice, there are some good tidbits for anyone worrying about managing their data center more efficiently. The ideas are things that European Union companies are being encouraged to do voluntarily. Sun Microsystems has jumped on the bandwagon to support the suggestions, which means providing power information for its equipment, spelling out humidity and temperature limits in its product warranties, and developing training programs.
Here's a link to the EU specifications PDF, which you can download for your own edification.