Popular Mechanics ran an interesting feature. They presented each of the candidates views on a number of issues that are of interest to their readers.
Among the issues was space exploration. According to Popular Mechanics only two of the candidates have any view at all. Both of those are Democrats, Hillary Clinton, and Barack Obama. According to PM, none of the Republican candidates weighed in on this issue!
I did a little hunting around and found that most of the candidates have reported views on space exploration. Links to the views of the rest of the candidates follow.
Ron Paul: This is a link to Ron Paul's stance on privatizing space from 1988. There doesn't seem to be anything available after that.
John Edwards: The following link describes what Kerry and Edwards thought about space in the 2004 election. They didn't come out with their views until days before the election last time, maybe Edwards is waiting again this time.
Rudy Giuliani: Giuliani spoke on the future of the space administration on January 18th.
Mike Huckabee: CNN had a few words on Huckabee's response to a debate question regarding the space program.
John McCain: McCain's views are summarized here with an attribution to his campaign site.
Mitt Romney: A few notes from a Fox News blogger on Romney's NASA views.
If I've left out your favorite candidate, please let me know in the comments below, and I'll fire off an update!