OK, the facts laid bare for everyone:
#1) There is a well known Irish folk song, about a soldier who tries to decide between his love and his country, called "The Wind that Shakes the Corn." Done by The Irish Rovers, et al.
#2) Solas took the SAME lyrics of "The Wind That Shakes the Corn", put a NEW faster tune to it, and changed "corn" to "barley", thus calling it "The Wind that Shakes the Barley."
#3) "Harvest of the Moon," which is the song Kevin was searching for, is AN ORIGINAL SONG by Steeleye Span, and bears no resemblance to the songs mentioned above EXCEPT it happens to contain the line "the wind that shakes the barley".
I hope this sorts out the confusion!