This article discusses the "broadband divide" in Washington D.C., which relates to the idea that high-speed internet access should be how we measure the digital divide, since anything less seriously impedes an individual's ability to engage with the Internet on the level that those with high-speed access are able to
One aspect of the digital divide includes urban-rural connectivity disparity. Jessamyn West is a rural librarian and advocate of bridging the urban-rural digital divide. The above link is to the audio recording of Jessamyn's facilitation of the "Offline America" session at last year's SXSW (South by Southwest) conference. You can get the lecture notes, slides and more here: http://librarian.net/talks/sxsw2011/.