Unless you're travelling from the UK, you will need an adapter to use your electric appliances in Ireland.
We use a three pin plug in Ireland, with square pins.
You can buy electrical converters/adapters in most airports, and all over Dublin city centre. For example, you'll find US to Ireland plug adapters on sale at Boots, a pharmacy chain.
The voltage in Ireland is 240v. Check that your appliances work on a 240v system. This should be stated either on the device or in its manual.