Miss McGill has just inroduced me to this interesting search engine that is powered by Google.
http://www.blackle.com/
Blackle was created by Heap Media to remind us all of the need to take small steps in our everyday lives to save energy. Blackle searches are powered by Google Custom Search and saves energy because the screen is predominantly black.
In January 2007 a blog post titled Black Google Would Save 750 Megawatt-hours a Year proposed the theory that a black version of the Google search engine would save a fair bit of energy due to the popularity of the search engine. Since then there has been skepticism about the significance of the energy savings that can be achieved and the cost in terms of readability of black web pages.
Why don’t you set Blackle as your home page and each time you load your Internet browser you will save a little energy. Remember every bit counts!

Hi there, I have a feeling that the whole “Black Google” idea may just be a good piece of marketing on the behalf of Blackle.com, google have denied reports that it saves any energy on monitors and due to the way in which TFT monitors display colours there is actually evidence to suggest black uses more energy than the traditional white Google page.
The below link gives a quick insight into the situation,
http://www.quickonlinetips.com/archives/2007/09/google-clarifies-black-google-blackle-may-not-save-energy/
By: Mark on September 18, 2008
at 2:19 pm