Is there an app for that?

If you could make my iphone into a defibralator

That's a great idea but it already exists: http://goo.gl/XHzAy
Thanks mate

I think you're looking at it from the wrong angle. There are already thousands of web sites which ask people to click on a link, or to view an advertisement, in return for which the advertiser donates to a cause. That doesn't require a special application, and those web sites can be accessed from any smart phone. Perhaps what you would need to do would have less to do with creating an application than it would creating a clearing house for charitable contributions which people could make with their smart phones by adding the cost of the contribution of their monthly bill. The application wouldn't be rocket science--the problem would be in coordinating the charitable contributions.

Thank you for your answer Setanta.
I think you've got a great idea, it would be interesting to have a kind of tax for charitable contributions "offered" by the carrier. I'm going to look at this option.
I'm just looking for an idea related to a smartphone app because this is what I'm good at and I'm seeing huge amounts of money everyday for this. I'm sure there's something to do in that field.

I agree. Already, in Africa where smart phones are about the only sophisticated technological devices which are widely possessed, all manner of financial transactions are carried out using smart phones. People use them to buy ordinary household items when they do their shopping. I suspect what you need to do is to get together with people who work with charities and figure out ways to use the billing on a smart phone to contribute directly to the individual's charity of choice. It would work even better if there were a way to assure the donor that the money is going directly to the charity they choose, with no money being skimmed off before it reaches their chosen charity.

There are tons of things you need consider in designing especially if you are considering a apps.