Thanks to Adam Bogobowicz for providing me with a link to this new tool.
You can think of this site as a tools designed to help quantify the environmental and cost savings benefits available through Microsoft virtualization technologies. It can build a simple environmental savings report for server virtualization projects and provide access a deeper set of tools, like scenario-based ROI analysis or infrastructure assessment. The site is found at www.hyper-green.com
I did a very basis ROI analyis and found that just consolidating 35% of my servers for an example company resulted in cost savings enough in energy savings alone to justify the software expenditure.
Try out the ROI tool for yourself!