I'm going to give you a few ideas for those of you with smart phones/tablets that can use iTunes apps- and I think all the ones I'm recommending are free:
XE Currrency- a simple, free app to keep track of conversion rates.
Skype- if you can get internet access (and our hotels should have wi-fi, perhaps not FREE- but I'll be checking on that) you can talk/video chat with loved ones back home and forget about international calling rates.
Rick Steves Audio Europe - fan of the travel man? You can download his audio tours by country.
Triposo Ireland / City Walks: Galway (Lite) / City Walks: Dublin (Lite)/ Ireland Hidden Gems - 4 different but similar apps that give you basic info and local maps.
Trip Suite- I have not played with this one at all, but it appears to be an aggregation of walking tour, shopping and cuisine finder apps-- with space for trip planning-- but again, it's all theory to me!
One more thing- on a pilgrimage tour, so much of your time is planned out for you that a guide book might not be very necessary. Still, it can be a good way to learn about the country and local information. If you have a Kindle or Nook or any kind of e-reader (or the free kindle app on your phone/tablet), you could buy an e-edition of a guide book- IF you wanted one at all. You can probably also borrow one (a guide book) from the local library.
Okay then-- send me more tips, please!