OpenTraceOpenTrace is a wiki-based database of information about products which can sum up the embodied environmental impact of products from bread to airplane rides to buses to anything. There is a demo of it here, as presented at TechCrunch50 recently. (The first half of the video is banter while setting up the demo—skip to the middle.)
This CNET article tells more. Still in early alpha, and they are looking for funding, but it could be very interesting if it comes to fruition. They say it will soon be up in demo form at OpenTrace.org.