Here's a question that I have been trying to find the answer to for a while. I am looking for a listing of how each state chooses presidential candidates at the state level. I know a few (Iowa-caucus, Illinois-closed primary etc.) but am having trouble find a list for all 50 states.

http://www.thegreenpapers.com/PCC/StAll.html

I don't know if this is quite what you are looking for. But what it shows is when the states held their Presidential Primaries.

I hope that it is at least a step in the right direction in answering your question.

States don't choose presidential candidates per say. Politcal party's choose presidential candidates by having primary elections in each state. Based on the results of the primary, each candidate is awarded a number of delegates who attend the national party convention. At the convention the delagates cast their votes for the candidate they represent (they're not legally bound - and sometimes they switch) The Party's candidate is then selected based on the outcome of the delegates votes.