The iCrossing Blog posted screen captures of Google experimenting with green in the Google user interface. In addition, Google has changed from the yellow background color for their ads to green, within the Google Directory. iCrossing actually reported this two weeks ago but I I missed it until I spotted a Search Engine Watch Forums thread on his findings.
Here is a screen capture of a search on ipods at the Google Directory:
I see that green user interface myself, but I don't see the green look at a normal Google web search, like iCrossing showed for a search on car insurance.
It may be that iCrossing has a browser cache issue from moving from the directory to web search? Maybe? I am not sure.
Forum discussion at Search Engine Watch Forums.