According to the Nespresso website (www.nespresso.com), the machines are available in the BT family of stores - Cashs of Cork, Todds of Limerick and Moons of Galway. I've seen them for sale in Harvey Normans too. There are several manufacturers of nespresso machines (Krups, Miele, Magimix).
The capsules and other items (crockery, etc) are sold in Brown Thomas, Dublin, otherwise it's mail order via the website.
I've just seen your post on Nespresso machines. There are a list of stores where they are available on the website www.nespresso.com. Off hand I know in Limerick you can get them in Harvey Normans and Soundstore in the City East Retail park and in Cork any of the Soundstores and again in the Harvey Norman also. Brennans cook shop in Cork City also stock them.
Regarding the coffee..ordering online or on their freephone service is best for these regions, unless you are up in Dublin and can pop in BT on Grafton Street. They have their own Coffee Bar style corner there where you can buy the capsules.