Republican Party process
For the Republicans, the Iowa caucus follows (and should not be confused with) the Iowa Straw Poll in August of the preceding year. Out of the five Iowa Straw Poll iterations, 1987 is the only year in which the winner of the Iowa Straw Poll has not gone on to win the Iowa caucus.
In the Republican caucuses, each voter casts his or her vote by secret ballot. Voters are presented blank sheets of paper with no candidate names on them. After listening to some campaigning for each candidate by caucus participants, they write their choices down and the Republican Party of Iowa tabulates the results at each precinct and transmits them to the media. [1] The non-binding results are tabulated and reported to the state party which releases the results to the media. Delegates from the precinct caucuses go on to the County Convention, which chooses delegates to the District Convention, which in turn selects delegates to the State Convention. Thus it is the Republican State Convention, not the precinct caucuses, which select the ultimate delegates to the Republican National Convention in Iowa.
http://en.wikipedia.org/wiki/Iowa_caucuses#Republican_Party_process