Want to give to worthy causes without actually giving any money? There’s an app for that. It’s called CauseWorld and is currently available for both the iPhone and the Droid.

Here’s how it works: You download the free app to your mobile phone. Then you visit one of the project’s retail sponsors and “check in” using your phone. No need to buy anything, no need to even talk to a sales rep.

The app registers your presence and awards you good “karma” points, which you accumulate and donate to the nonprofit of your choice. Users are encouraged to spread the word about their good works via social networking sites such as Facebook.

Proctor and Gamble said it will give users karma points for scanning the bar codes of 27 products, like toothpaste or face cream. And now Citi is expanding its support of CauseWorld. It’s adding two micro-finance outfits to the list of charities that can receive users’ karma points.

The app also lets you create a profile and earn different levels of merit for using the software and helping the world.

Most important of all, the 300,000 downloads of CauseWorld have caused investors to flock to the company’s developers. Now that’s how to raise money.

The CauseWorld App is available for free from the App Store on iPhone or  here.

Tags: CauseWorld, Citi, droid, iphone, Proctor and Gamble