At 74% precincts reporting in the SC primary, the numbers are at: Obama (54%), Clinton (27%) and Edwards (19%).
I did some calculations using exit polls (using gender cross tabs):
which estimate gives roughly the same numbers.
I also did some computations using Pollster.com's SC polls page, and interestingly, Hillary led Obama in monthly averages all the way till December:
Here is a plot of the polling numbers in SC for Obama, Clinton and Edwards over the course of the campaign since December of 2006:
which shows that Clinton led most of way through November and by whopping margins at many times during that period.
The spreadsheet for all of these computations is here.
Clearly, Barack Obama has posted a dramatic comeback victory in South Carolina. Congratulations to Team Obama!