The Federal Communications Commission (FCC) released the nation's broadband access map yesterday. It's an interesting look at what areas are connected via broadband. It is in line with population density. As you can see, broadband is most prevalent on the East Coast and rolling into the Mid-West (which incidentally is still very, very east if your on the West Coast). This report goes along with a proposal to increase broadband access through the Connect America Fund.
An older (cir. 2000) population map of the US via visualizingeconomics.com originally created by Joe Lertola for Time Magazine.