When you donate $399 to The One Laptop Per Child (OLPC) project they will send one laptop to your child and one to a child in a developing country. This ends December 31, 2007. $200 of the donation is tax deductable. (since you’re getting one of the laptops). Shipping and handling is extra.
If you don’t want one for your child you can simply donate $200 for each laptop you want to send to a child in a developing country.