Intel launched a site named…
LessWatts.org
…whose slogan reads Saving Power with Linux on Intel Platforms.

Microsoft has an OfficeLive promo site that promotes its green side. You can find it at…
Green Business

The new Earth2Tech blog is part of the GigaOM blog network. It focuses on green tech startups.

Here’s a website that helps you find a nearby recycling center (if there is one).
The Recycling Center
Just type in a zip code and click the search button. It displays a Google Maps mashup with pushpoint identifying recycling centers. I wish it would list what kind of recycling each center performs though.

Not exactly a green topic, but close…
ClimatePrediction.net
…is one of those donate your unused cycles for massive computation projects. Of course, if you leave your PC on all the time to contribute to this…
I wonder if there is a way to combine tasks like virus-scanning (for Windows boxes) or other long running tasks with these net-parallel [...]