WITHOUT A DOUBT, the most helpful piece of technology I can recommend when visiting Ireland is a MAXroam SIM. This little sliver of plastic will keep your mobile phone bills well within budget. In my own experience, the shock from mobile phone roaming charges hurts more than lost luggage. I bought my MAXroam SIM from Maplins in Limerick for €41. I purchased the little SIM even though no one in the shop really knew what it did. I knew because I had seen the Cork-based Cubic Telecom profiled during a special conference in Paris. Dozens of technical reports followed that technical demonstration and gave me the confidence to buy a new SIM for one of my older mobile phones. You need an unlocked mobile phone to make the SIM work.