I have been using this site for the last couple months. Its a great idea. Basically instead of just handing money to a charity to dispurse as they see fit, you help fund microfinance loans (still administered through a charity).
This means it helps break the 'hand out' mentality, and allows people in less fortunate areas begin to earn money for themselves.
You generally only get your money back on your loan (no interest), but its a good feeling to know you are helping people change their lives for the better