What would be the most convenient and least expensive way to call? Should I purchase and international calling card here in the US at a Sam's Club for example?

Cheapest would be to buy a calling card after you are in Ireland. They are available in most news agents, mini marts-type shops, etc etc . . . .

My wife is going to Ireland with her sisters on Saturday. She is a great researcher and found out that using an international calling card (Sprint in our case) from Ireland costs 19 cents a minute, but calling from the US costs 5 cents. So if you can get your stateside friend or relatives to call you, you would save. Plus, if cost is really important to you, buying a card in Ireland after exchanging your cheap dollars for a paltry number of Euros might be even more expensive. Of course, the other side of this is that spending a few bucks on calls might be a negligible cost compared to the airfare, B&Bs, food and Guinness.

The cheapest way to call the US from Europe is via skype which is free. You can do that from a laptop or most internet cafes.

Davethecat65: Actually - a calling card bought in Ireland will be cheaper than 19¢ a minute. depending on which card one buys - calls will run from around 7¢ to 12¢ a minute.

The Sprint/AT&T-type cards from the States will be more expensive for phoning home.

janisj- thanks for that info. I will let her know, although at this point, our plan is for me to call her. As if she will be able to hear the phone when she is at the pub!