Forestle.org has been launched and is a Custom Google Search Engine that claims 0.1 square yards of rainforest are saved with every single web search.

<< Forestle is a "green Internet search engine". We use our advertising revenue to protect endangered rainforest regions in order to keep our worlds most precious ecosystems intact and fight global warming.
   Forestle earns advertising revenue from clicks on "sponsored links", which are displayed next to the normal search results in our search engine. These sponsored links are delivered by our partner Google. >>

http://www.forestle.org/

Source: Ars Technica
http://arstechnica.com/news.ars/post/20080825-forestle-turns-google-searches-green.html