Click to give sites are nothing new, but some people are still in the dark. In case you don't know, click to give means that every time you press a particular web-button, a sponsor gives money to a cause. It's effortless.
The site that I first encountered was the Animal Rescue site, which covers so much more than just feeding shelter animals. You can also support the protection of the rainforest, free mammograms, literacy, health care, and ending hunger. Click to give.
Care2 has a similar page. Here you can click for the rain forest, seals, oceans, big cats, primates, children, pets, ending violence, and ending breast cancer. And it's all on one page to make it even more convenient. Care2 Click to Donate.
Another site I'm grouping in this category is GoodSearch. It's not actually a click to give site, but it's a search engine that donates to an organization that you specify every time you use it. It's powered by Yahoo!, and it's nowhere near as expansive as Google, but is that really more important than giving to a great cause - for nothing on your part? GoodSearch.