I'm getting married tomorrow, and my new wife and I will be honeymooning in Ireland form May 30 - June 9. We've got the first 2 nights' accomodation booked in Dublin, then we plan to drive around the South (Kilkenny, Cork, Killarney, Dingle) and then fly home out of Shannon. At this point, we probably won't be able to make any more reservations for lodging until we get there. Do you think we'll have an OK time finding lodging on the fly? (I just learned about the Spring Holiday weekend, and got worried).
If you're renting a car, you should be able to find accommodations on the fly without too much headache.
Booking rooms from the tourist office can be a big help. They can book anywhere in Ireland, so you could make a few bookings at one time. I often stop in the tourist office in the morning when they tend to be less busy, book a room in the town I am heading toward, finish up my touring, head to the place I have my reservation to check in at around 5:30 and ask the host for his or her recommendation for a place to eat.
You can also get an accommodation guide at the tourist office.
If you know where you are heading, your host may have a suggestion on where to stay (many times they'll make the call for you).
Having a Lonely Planet, Fodor's, Frommer's or Michele's book handy can be helpful as well.
If you don't pre-book, you'll want to start looking for a place to stay at 2 or 3pm. If you wait until after 5, you might find yourself spending a lot of time running around.
Congrats on your wedding! Corey has given you some excellent tips on booking B&Bs as you go. I wanted to add that June 2 through 4 is a Bank Holiday weekend in Ireland. Monday the 5th is the actual day off but everyone in Ireland will head off for a long weekend clogging up accommodations. That could be a problem, depending on where you want to be. If it is a very popular area like Killarney, Dingle, Kinsale, etc. then you will want to make some reservations for that weekend. You might consider doing it as soon as you arrive in Ireland. Take a look at some of my recommendations on my "Lodgings" page.
I don't know you from Saint Patrick, but I just wanted to write and say to you and your bride: Congratulations and have a wonderful time!
Tell you what I learned. Just being in Ireland is so fun, exciting and romantic, you don't have to hurry or strategize to be in the "right" place, because every place is the right place!