Here's a list of some of those available on Napster.
I've listed only the ones I like.
The Dooley Brothers
The Travelers -- especially nice harmony -- a little bit different - nice blend
Makem and Spain -- a capella version
Shenandoah Trio -- really nice live performance
Brooklyn Blowhards trumpet and jazz band version -- may have had too much to drink
Muirsheen Durkin version -- folk-rock interpretation
Barquentine -- female jazz/blues interpretation
Dan Furmanik -- nice folk interpretation with drums accompaniment.
Castletown -- live performance
Woods Tea Company --