The Cloud Phone was intended to serve this market. At first Waller tried to create a cell phone that could be manufactured for just $5 so that everyone could afford one, but he couldn’t pull it off.

Instead Waller went with a $25 phone, but designed it so that a village of users could share it while still maintaining individual phone numbers accounts on a single phone. Activation cost? Just 10 to 20 cents per person.

The Cloud Phone is a service that allows people to have their own identity, and to log in and log out of other people's mobile phones, just like you can log in and out of your e-mail account using someone else's PC. In this way users can have their own personal mobile number for private communication, at half the cost of a SIM card and without the hassle of carrying a SIM card around.

When a user logs in with their own number and pin code they will be greeted with a menu. For example it says, "Hello, John. Your balance is $1. You have two missed calls. You've got one SMS message."

The Cloud Phone was developed by Movirtu and Frog Design, after they met at the PopTech conference last year, and the development process included a field study with 12 residents of the Kibera slum in Nairobi, Kenya.

Links

core77: http://www.core77.com/blog/object_culture/movirtus_cloud_phone_is_mobile_for_...
CNN: http://edition.cnn.com/2010/TECH/innovation/10/21/cloud.phone/index.html
Frog Design: http://designmind.frogdesign.com/blog/mobile-impact-at-socap-2010.html
Movirtu: http://www.movirtu.com/

Village phones have become a profitable business for mobile service providers such as Kenya’s Safaricom, which is 40% owned by Vodafone Group. Safaricom is even promoting a village phone brand called Simu ya Jamii, which is Swahili for “community phone.” 

However, as more people in the area acquire their own phones, and village phone operators proliferate, it has become harder to live from that income alone. Most village phone operators also sell other products such as bread or soda, or cooked food. Other extra services include taking phone messages for regular customers and the provision of a kind of ad hoc banking service, in which customers send money to their families by transferring electronic airtime credit to the village phone entrepreneur, who then passes on the equivalent in cash minus a small commission then resells the airtime minutes to other callers.

Full article and image gallery from Business Week:

http://images.businessweek.com/ss/07/09/0913_africa/index_01.htm