I also make micro loans through Kiva, which was recommended by Al Gore on some talk show I saw awhile ago.
I love the idea of micro loans because Kiva pools your money with money from other people and you get the feeling you can actually help someone without spending more than $25.
The nice thing about Kiva is that once your loan is repaid, you can reloan the money, so your actual expenditure is not as large as it might be. I've made 27 loans, helping 27 different people for really only about a $50 outright expenditure over the past 3 years. (There is also the option to have the money returned to you once it is repaid)
I usually choose women for my loans. My favorite loan was to a woman who wanted to build her gin-selling business (any gin lover is OK by me!). My latest loan is to Digna Isabel Preciado Ferrer, who is in paper sales. I figure that's like a stationery store, and lord knows I do love me a good stationery store!