Cisco recently released their, "Global Mobile Data Traffic Forecast Update, 2010-2015". There is more data here than most of us can handle. Here are a couple charts I found interesting.
Though the developing world lags the developed world in mobile data usage it is growing. As these folks begin to "see" how good we have it in the developed world they are going to work very hard to try and have the same. Luckily I don't think development is a zero sum game. All boats will rise on the power of mobile devices to connect each of us.