Mike McGoldrick follows Dirk Powell's version closely (Transatlantic buddies!) - pushes the key a bit I think. So I would suggest you look for Powell's version. There are lots of tabs out there for that one - many will be banjo though.
Here's a start for you. MOst versions I have played along with guitarists at festivals use EM G D C as the chords. Like they ask in Bluegrass circles, "Do you know the chords to...?" Response is usually, "Yep, I know all three of 'em". ... and everything is in G.
This might help as well.
http://mudcat.org/thread.cfm?threadid=130431 Interesting discussion going on there too.
Then, if visuals help, there is this:
http://www.youtube.com/watch?v=qseCR7QfRWg Skip the first minute - unless you want to know how McG tunes as well.
Keep in mind as you search that there is another traditional American song called Waterbound which may have inspired this one a bit. It's a bit more fun sounding.
https://www.youtube.com/watch?v=FsuoI_k9grQHope that helps.
Feadoggie