Mobile phones are widely used in both rich and poor countries, unlike what happens with other ICTs. The expansion of mobile telephony in poor countries presents an opportunity to fight against digital divide. In the latter countries, mobile phones are used to get information and services about agriculture, health, and education among other areas. Specifically in the area of education there are many who think that mobile phones are a useful tool to help achieve universal primary education, one of the Millennium Development Goals proposed by the United Nations. There are many educational experiences with mobile phones for development. But most of these experiences have serious limitations that affect their long-term sustainability. In this line, the current paper provides a set of guidelines to define more sustainable and long-term viable mobile-learning projects and presents its applications to a m-learning project: the Moodbile project.