This posting is not about the Jameson or Bushmills type of spirits--so off you go to a pub if it's whiskey you are seeking.
There are tales of local hauntings all around Ireland. You can find these stories many ways. I have seen reports of spirit sightings in local Irish newspapers from the 1800's. Search the internet for tales of the supernatural in Ireland. When you go to Ireland, book a local "ghost" tour. These tours are springing up all over the country, particularly in the cities. Cork City has its own Irish Ghost Family Festival each September. Don't forget to search local libraries and book shops for tales of local lore. Ask locals if they know of any hauntings nearby.