"M-PESA is a world-renown service which allows users to transfer money using a mobile phone. It is offered by in Kenya by Safaricom, Kenya’s largest mobile phone operator, and part of the Vodafone Group. Registration is free and available at any of the thousands of agents spread all over the country. The M-PESA application is installed on the SIM card and works on all makes of handsets.
M-PESA customers can exchange their cash into credit at a Safaricom dealer, then use their mobile phones to transfer their money across great distances to another mobile phone user. There is no lower limit, and the money can be sent to registered and non-registered users alike." (http://www.thinkinnovation.org/en/blog/2010/11/new-innovation-case-on-think-m-pesa/)