As usual, Rasmussen has the best polls and analysis of the race so far. Read the whole thing -- it's required. But here's the key bit:

...among those who are “certain” they will participate in the caucus, it was a bit closer—Clinton 29% Obama 28% and Edwards 22%.

Among those who have participated in the caucus before it was Obama 26% Clinton 25% and Edwards 24%.

Slight adjustments to the expected turnout produces a variety of results, but none that show a clear leader in the race.

Adding to the closeness of the race are the second choice rankings. Edwards is the second choice for 28% while Obama is the number two pick for 22%. Clinton and Bill Richardson are the second choice for 15%. Second choices are important for two reasons. First, because 26% of Likely Caucus Participants say they might change their mind. This includes 8% who say there’s a good chance they could change their mind.

I expect that the strong preference shown for Edwards as the second-choice candidate isn't going to propel him to victory. If you take the bottom five Democratic candidates, the ones least likely to break the 15% threshold, you barely get more than 10% of the total vote. Give 40% of that to Edwards and split the rest between Obama and Clinton, and it's still too close to call.

Best guess for the final tally, after stripping away the non-threshold guys and splitting their votes: Obama 37%, Edwards 32%, Clinton 31%. Yeah, I really do think it will be that close.

NOTE: Of the limited number of independent voters willing to brave the cold, I expect more of them to show up and caucus for Ron Paul than for Obama. Obama is good, but he doesn't generate the excitement Paul does -- especially not among anti-war folks who want to stick it to the Republicans. If anything can stop Obama from winning tonight, that's it.