The use of cell phones is interesting in how it relates to transforming the rural/urban power divide within the developing world. This isn't something entirely new, rural community radio stations have played very large roll in communication and social transformation. In Bolivia, the revolution of 1952 lead by the miners unions, was coordinated by a network of rural community radio stations. With high illiteracy, little infrastructure, very poor communities these communities have relied on radio as the primary form of mass media.
In the last decade there has been an upsurge in the political power of indigenous movements in the Andes who have their power base in rural mostly disconnected communities. A lot of that upsurge is due to the many years of organizing by indigenous leaders, social movements, and NGO's. That said, cell phones have acted as a major amplifier of their work. Increasing the ability for people to coordinate their actions and build robust social networks.
Unfortunately, I've not seen much written about the use of cell phones and other communications technology in the general strike and 'Gas War' in Bolivia last month. From my working with the rather small group of indymedia people in Bolivia i've heard some of how cell phones transformed the conflict. It helped people lay a more than week-long siege to La Paz. It also helped coordinate the marches of people from other parts of the country to the capital. When women went on hunger strike in churches the communications network made it a coordinated act, not simply the act of a few brave women in one location.
I think what happened in bolivia is quite different than the much talked about 'smart mobs' as there were relatively few people will cell phones. The groups were not flexible, but rather quite well organized with cell phones used to coordinate between the leadership of existing organizations and networks. The use of cell phones facilitated the biggest indigenous siege of La Paz in almost 300 years.
Other important factors was Pios Doce and other community radio stations which played a vital mass media roll during the crisis. The Pios Doce transmitter in Oruro was bombed, by people who clearly didn't expect the police to investigate anything. What the government didn't figure out how to do was shut off the cell phones of known organizers, or towers which serve indigenous communities. My guess is the reason they didn't shut them down was in part because cell phones were a vital communications tool for the police and army. Even the US Army in Iraq makes extensive use of consumer walkie talkies and unencrypted Instant Messenger. In India Texting has been shut off at critical points to stem the spread of rumors and coordinated race riots during communalist uprisings in the last year. I expect as social movements turn to using cell phones and related technology as a tactical tool during protests and uprisings the governments will eventually learn how to turn off the ability to communicate at will.