If you search from here: http://www.goodsearch.com
they will donate 50% of their profits for you. You get the same results as you do from Yahoo search. You type in a word (e.g. "cats," or "animals") and it finds a bunch of charities for you. Then you pick one and it sets it, so that all your searches support that one.
You can also shop online through: http://www.buyforcharity.com/
and they will donate a percentage of your purchase to the charity of your choice. There are other sites like this.
Those sites will give you a lot of charities you've probably never heard of, and you can find local ones too.