Download the iKiva app, and walk through the list of loan requests with your child.
A loan request would have details of the borrower, project and repayment terms. For example, there is a Mary under the project category of Agriculture. She is from Nyamira, Kenya and is requesting for US$725 to buy a dairy cow so she can sell the milk. She has already raised US$250 with 14 months as the repayment terms. There is even a picture of her and biodata: she is 43, a farmer and widow with 7 children, all of whom are in school.
Talk to your child about these countries and their people, why they are poor and process with him which one(s) he wants to help. It can be as little as US$25 or as much as the entire amount. The borrower will repay the loan after a certain period of time. Lenders can then choose to donate that amount to Kiva or withdraw the money.
Do note that the risks here are like investing in any other third world business and the money might not be returned in full (or at all).
Nonetheless, this app is a great way to educate a child about the needs of others and to create an awareness and appreciation for what he/she already has.