The new Des Moines Register poll has Mike Huckabee in the lead in Iowa by a 5 point margin.

Huckabee 29%
Romney 24%
Giuliani 13%
Thompson 9%
McCain 7%
Paul 7%
Tancredo 6%

On the Dem side, Obama's in front but by a slightly smaller margin ...

Obama 28%
Clinton 25%
Edwards 23%
Richardson 9%
Biden 6%

Remember too that there's a significant wildcard factor in the caucus system. It's not a straight one person one vote. People meet at their caucus locations and candidates with less than I believe 15% of caucus-goers at that caucus have to either switch to another candidate or into an uncommitted group. The key point is that who peoples' second choice may be can have a powerful effect on the outcome -- one not necessarily revealed just by looking at a conventional poll.

In this case, the top two Republicans and the top three Dems each appear well over 15% support. But remember, that's statewide. In individual caucuses you're going to have a lot variation. Especially on the Democratic side, the second choice could be key.