From USA Today (scroll down):

7:24 p.m. ET: Youth turnout high
Younger voters are turning out in larger proportion this year, compared with 2000. Seventeen percent of those surveyed in early exit polls were between 18 and 29 years old, compared to 9% in 2000.
One result of having such stark issues: people made up their minds earlier. In 2000, 69% said they had made up their mind more than a month before the election. This year, 79% had made up their minds a month before the election. Late-deciding voters broke in Kerry's favor, and those who decided sometime in the first few weeks of October (think debates) broke strongly in favor of Kerry. Early deciders were split.

Early exit polls showed women going to the polls in disproportionate numbers: 57% of the voters are female, 43% male. In each of the last three presidential elections, the proportion was 52% female, 48% male.
More voters listed moral values as the issue that mattered in their presidential vote, followed closely by those who listed the economy/jobs and terrorism. Seventy-nine percent of Bush voters said moral values mattered most, compared to 22% of Kerry voters. Kerry voters were mostly likely to cite Iraq and the economy.