I know Bush has been leading the popular vote all night, but I just took a look at the CNN national exit polling, which has already been posted.
Consider the demographic data...actually there's no need to be complicated. I was going to break it down by all the ages, but CNN conveniently provides this simple split of the data:
Ages 18-64 Kerry 51, Bush 48 (84% of electorate)
Ages 65 & older Kerry 50, Bush 50 (16% of electorate)
Quick, tell me who won the popular vote?
It looks like about 50% Kerry to 48.5% Bush.