I've mentioned this project before, as it's an interesting gathering of green techies coming together to produce a collaborative piece based on current Green IT principles, thinking and concepts. The subtitle of the book - 'How Greener IT can form a solid foundation for a Low Carbon Society' sums it up rather well. Each chapter is written by one of about a dozen contributors from all over the world, and covers a different aspect of Green IT. Here are some examples of the topics covered:

Why Green IT Is Hard - An Economic Perspective
Cloud Computing
Thin Client Computing
Smart Grid
How IT Contributes to the Greening of the Grid
The Green IT Industry Ecosystem
Out of The Box Ways IT Can Help to Preserve Nature and Reduce CO2
From KPIs to the Business Case - Return on Investment on Green IT?

The great thing about this approach is that each chapter is written by an expert in his or her field, so it's all very current and accurate, as opposed to being written by one person who knows 'a bit about each topic'. I find it easy to read (esp. with my short attention span) as you can dip in and out as topics grab your interest. Here's a snippet from chapter 4-Why Green IT Is Hard (one of my favorites)

You could say there are technical, financial, legislative, compliance, and moral triggers to act and cut down energy usage. But are data center operators taking action to measure coming energy and carbon emission regulations? In several reports and presentations contrary observations are made. For example, according to Christian Belady at the DatacenterDynamics conference in Seattle 2009, 17 percent of data centers in the U.S. track carbon emission. On the energy-efficiency side, Power Usage Effectiveness (PUE) is one of the most commonly
used metrics, and formulae for its calculation and other metrics are also widely available, but also according to Belady only 15 percent of data centers do such measurements.
If we maintain the current modus operandi, “energy consumption by servers and data centers could nearly double again in another five years” in comparison with the year 2006 (Program, 2007). There are many drivers to act on this enormous energy consumption growth and
those drivers are not new. Also there are many technical solutions to improve energy efficiency. So what’s missing here, why is IT not so much greener than it is today? And isn’t Green IT a requirement for using information technology as a green technology, Greening IT, that can transform our societies into low-carbon equivalents?

You can download the book for free, or hold it in your hands in paper form from Amazon ($18) or other vendors. I think a kindle version is planned but the link wasn't working when I last looked.

Aside from the relevance of the content, I think this is a great example of collaborative working within the IT industry and I only wish that there was a lot more of this kind of thing around. Best of luck from 1E guys!

You can find the book here:- http://greening.it