The recent polls have Gingrich up on Romney by anywhere from 2% (in other words, tied within the margin of error) to 9%.
I'm leaning toward the higher number, not because of where it comes from (PPP -- not the most reliable polling service), but because Gingrich and Paul's supporters are energized and Romney's aren't.
Prediction as South Carolinians head to the real polls, +/- 2% on each candidate:
Hey, I predicted three of the four candidates to within 2% of their actual performance! I'm surprised Paul didn't make third place.