Tech giant Dell has created a specific site where you can shop for Dell technologies that are explicitly designed (or marketed) as green, from both a materials standpoint and from an energy-efficiency standpoint.
The site, if you think about it, is really just a subset of its existing e-commerce offerings. The products picked for exposure must comply with at least one of the usual-suspect standards you'd expect: Energy Sta and EPEAT. OR ones that you might not be as familiar with, such as the TCO Certification, which combines environmental standards with ergonomics ratings, or Blue Angel, a German eco-friendliness label for technology.
What's kind of cool is that the store includes not just Dell-branded products but other technologies that were designed with environmental considerations in mind. Vendors featured include 5dot, American Power Conversion, Belkin, Mitsubishi Electronics, MobileEdge, Netgear, NuoTech, Samsun, Sony, Targus, Tripp Lite, Vizo and Western Digital. The metrics for getting onto the site include the energy efficiency of a given product, power management features, what its made out of, and recyclability.
I poked around a bit to see which other tech giants do the same thing as far as organizing their web sites to find the greenest tech most easily. I found something similar on the Hewlett-Packard EcoSolutions site, although it isn't exactly an e-commerce site. I also found this incredibly handy list of eco-tech certifications, that clued me into some standards I didn't know about.
Some of the online e-tailers that specialize in technology HAVE moved in the direction of grouping together their green IT products so that you can find them more easily, including Staples with its EcoEasy site. The Consumer Electronics Association put together an informational site for consumer electronics, and there also appears to be an EcoTechnology section in the Whole Green Catalog, although I'm not sure how deep either will go for the likes of you IT managers reading this post. If there are lots of others out there, I would love to hear about them. Otherwise, I am sure that if you care about how green a particular product is, you're having to do your own research.