Prof. Michael McDonald over at GMU has done a great job of tracking turnout in this and past elections. He has posted preliminary rough turnout estimates on his blog. So was turnout up or down?
According to Mike, national turnout was 62.6% among the voting eligible population. Unlike the voting-age population, the voting-eligible population excludes people over age 18 who aren't eligible like noncitizens, people imprisoned and disfranchised felons. At an estimate of 62.6%, turnout is up 1.9% from 2004 and is the highest turnout rate among the voting eligible population since 1964.
Turnout was up in Maryland too--67.0% of the voting eligible population of our state cast a ballot this year compared to just 63.1% in 2004.