A two part (second part here: http://mindshift.kqed.org/2011/06/what-exactly-can-you-learn-on-a-mobile-phone-part-ii/) interview with Mimi Ito, an anthropologist focused on children and new media, about whether or not mobile internet is a valid tool in bridging the digital divide when it comes to learning/school. 

Follow along with five videos about life without the internet in rural North Carolina towns.  in 2007, about 30% of rural NC was without internet. Unfortunately, there hasn't been an update, but it's still a powerful case study

PDF of a book by Mark Warschauer looking at how access to technology contributes to social divides in both developed and developing countries.  

life /without/ a digital divide -- this case study takes a look at several groups of Japanese people in different age brackets and how they use - and are attached to - their mobile phones