CNN is calling it for McCain on the Republican side. Very interesting. With 13 precincts reporting, Clinton is at 40% to Obama's 36%. CNN says Edwards will come in third, as he's trailing at 17%.
UPDATE: It's still a close one between Clinton and Obama. You can see county-by-county results here.
UPDATE II: CNN is calling it for Clinton, with 72% of the precincts reporting.
UPDATE III: My own completely unsophisticated political analysis is that Obama's victory in Iowa was a little like a football time driving down the field for a touchdown on the first possession, and Clinton's victory tonight is a little like the other team responding with their own high-yardage, clock consuming scoring drive. In other words, the game is hardly over yet. In fact it's only just begun!