From the New York Times:

The ground war — the laborious, unglamorous process of identifying supporters and making sure they show up to make their preference known when it counts — has always been a critical part of the contest in Iowa. But the turnout effort among Democrats this time around has exploded into the most ambitious and costly in the history of this state’s presidential caucus system, and it puts on display the sharply diverging strategies the candidates are pursuing as they hurtle toward the first real test of the 2008 campaign.

Mrs. Clinton and Mr. Obama are trying to expand the tiny universe of caucusgoers, a fundamental shift in the way candidates have approached the Iowa caucuses. Mr. Edwards is focusing mainly on voters who have reliably voted in the past.

Programs include driving voters to the polls, babysitting, providing snow shovels, free food and more to entice, delight and get out the vote.