Gavin, over at Green Options has a great article on the top 15 charity search engines.
This is done mainly by providing a portion of the advertising revenue they receive to charity or green projects. The sites he has listed are:
– Magic Taxi
– Search Kindly
– Catch Tomorrow
– Clicks For Cancer
– Charity Café
– The Green Spider
To find out how each site helps take a look at Green Options for more details. If you know of any others, please add them below.