So Iowa does not have a say in the nomination?
Iowa chooses national convention delegates in June at the state convention. By then, the nominee will almost certainly be known and long-time party regulars will make up most of the delegates.
Affluent party regulars favor Romney, so he will be over-represented if the delegation is split. Assuming Santorum got Huckabee supporters from 2008, he will also be over-represented among national delegates from Iowa. I’d expect Paul to get about half the delegates he’d be entitled to were it actually proportional representation.