This brief paper outlines three kinds of development benefits resulting from mobile phone technology: (1) 'incremental' - improving what people already do; (2) 'transformational' - offering people something new for example mobile banking; and (3) 'production' benefits that result from the creation of new livelihoods. It argues that increasing mobile penetration brings developmental benefits, but effective regulation is required to ensure fair competition and encourage roll-out to underserved areas.