A few years ago, venture capitalists were pouring funds into internet startups. They still do, but now the new "hot" thing is green, and tons of young companies are trying to make it into the various fields of the cleantech sector.
Earth2Tech has created a Google Map with 101 CleanTech startups (there's a functional version of it embedded lower in this post). It is pretty US-centric, and within that country Silicon Valley is probably over-represented (though the entrepreneurial spirit over there is hard to beat), but it's still very interesting to explore. You might even find something close to you that you didn't know about!
View Larger Map
Here it is. Don't be afraid to zoom in and click on markers for more information. If that's too cramped, you can switch to a larger version by clicking on the link right under the map.
We encourage Earth2Tech to keep adding cleantech startups to it.