I have found a number of bits of information on early voting, links thereto, and a little data on 2008 comparisons. Credit goes mostly to the fine folks at USElection.org, their forum columns, but here it is in one place.
In short, Iowa voting appears well up. North Carolina voting is a small sample. In Ohio, your 'party affiliation' is the ballot you took in the most recent primary. The 2008 Ohio Republican Presidential primary and the 2012 Ohio Democratic Presidential primary were not contested, leading to some predictable but relatively meaningless movements of voters between nominal party affiliations.
The detailed information and fine links I found are below the fold:
Courtesy of John Deeth's blog
and the fine folks at USElectionAtlas.org, who found the link, Deeth wrote in 2008
Monday, September 29, 2008In addition, on Iowa for this year:
Democrats Have, and Need, Early Vote Lead
Democrats take estimated 30,000-vote lead in Iowa
Five weeks before Election Day, Barack Obama likely has a lead of more than 30,000 votes in Iowa, based on absentee ballot requests. But Democrats will need to continue their early voting blitz--they won the early vote in 2004 only to lose by a bigger margin on Election Day.
Through Thursday, the first day of in-person early voting, there were 62,024 absentee requests statewide from Democrats and 18,558 from-republicans. People not affiliated with a party have made 23,460 requests, and another 35 are from Greens and Libertarians
The first day of early voting in Polk County was busier than ever for election staff. By 4 p.m., 550 people had cast ballots at the Polk County Election Office. In 2008, 100 people voted on the first day but that number had been far eclipsed by 11 a.m. Of those, 401 were registered Democrats, 90 were Republicans, 57 had no party affiliation and two were affiliated with other parties, said Polk County Auditor Jamie Fitzgerald.Professor Michael McDonald's early voting site http://elections.gmu.edu/... covers many of these items as they emerge.