Your problem could be caused by condensation/moisture at the electrical connections in the ignition system causing the high voltage signals to find a path to ground. Remove the ignition wires one at a time, clean each end, and apply some dielectric grease before you reconnect them.
I once had the same problem and suspected that the fuel had frozen in the fuel rails (it was extremely cold and the antifreeze had the consistency of porridge) or the IAC was stuck. So I poured buckets of hot water on the engine and then was able to start it. (I don't know whether the IAC could cause this problem but that's what I thought at the time.)
Anyone else have any ideas?