Okay, so I already knew about Kiva, but I thought raising awareness about this organization would be fitting for Blog Action Day.
Kiva is a nonprofit organization, through which donors send money to microfinanciers around the world, who then lend that money to entrepreneurs in developing nations (and whose profiles are on the website). When the entrepreneur repays the loan (which, according to Kiva, happens successfully 99.7% of the time), you can withdraw your money from the program, or re-loan it to another entrepreneur.
Kiva has pioneered the peer-to-peer lending model, and other organizations have followed suit.
So, if I'm interpreting this correctly: your money is going directly to the person who needs it, you know exactly what the money is being used for, you can recycle your money through the program or just withdraw it and buy an iPod, and you're helping someone who's helping themselves. If you have some scratch lying around and are feeling altruistic, Kiva is a worthwhile investment.