Kiva

You don't have to give away money to support a good cause. At Kiva you can make a small loan instead. A unique peer-to-peer lending site that focuses on microloans, Kiva lets lenders pledge funds — from $25 and up — to entrepreneurs in developing countries. As of May 2008, that included a cattle breeder in Azerbaijan and a snack-kiosk owner in Indonesia. Kiva works with microlenders in recipients' native countries and typically pays you back within a year. If you're in need of funds yourself, try Prosper or Lending Club. And if you just want to make sure your cousin Bob pays you back your thousand bucks, try Virgin Money US, which administers loans between people who already know each other.

—Anita Hamilton