Very interesting blog entry at fivethirtyeight.com
FiveThirtyEight.com: Electoral Projections Done Right: The Black Turnout Surge, Already In Progress
"These are Georgia, where early voting is already at 180 percent of its 2004 total, Louisiana (169 percent), and North Carolina (129 percent). ... This works at the county level too. In Cuyahoga County, Ohio (Cleveland), which about 30 percent black, twice as many people have already voted early as in all of 2004. In Franklin County (Columbus), which is about 18 percent black and also has tons of students, early voting is already about 3x its 2004 total."