It's early to speculate. Perhaps Huckabee is even peaking too early. It's always hard to know with these things. But the polls out of Iowa now leave little doubt that Mike Huckabee isn't just surging or in the first tier. He may even now be tied with Romney
Now, Huckabee has little organization outside of Iowa and the classic problem of not enough money and infrastructure to effectively capitalize on a strong showing in Iowa. But the issue is less what a Huckabee "win" does for Huckabee as what it could do to Mitt Romney.
There's been a loose assumption for a while that Romney will sweep or at least dominate the early primaries. But if Huckabee wins in Iowa (and depending on the state of the expectations game a strong second could be a "win") it could be devastating for him.
Let's walk through it.
If Romney doesn't win Iowa then anything but a crushing victory in New Hampshire amounts to a loss since it's his backyard (a big chunk of New Hampshire is part of the Boston media market and many New Hampshirites work in Massachusetts). And if there's no momentum coming out of either Iowa or New Hampshire it's really hard to see how he does well in South Carolina since he's never been ahead there in the first place.
The Romney strategy is to capitalize on momentum coming out of the first contests just as most voters are really starting to pay attention to the race. But live by the mo, die by the mo. So much of the logic of Romney's candidacy is based on those early states and he's spent so much money to build up those leads, that an Iowa loss followed by the probable negative feed back loop would pretty much mean the Romney candidacy is over.
So you can see how a Huckabee win in Iowa, while probably not doing much good for Huckabee, could have a profound effect on the outcome of the GOP race.