This is really useful for a lot of sites in the central city (their studio, etc.):http://www.atu2.com/dublin/dublin-guide.html
Check out The Clarence
in downtown Dublin (Bono and Edge own it, and they'll occasionally have a drink in the Octagon Bar.) You probably won't have time or be motivated enough (unless you're a giant fan with an obliging DH, as I am), but you can see Bono's childhood home at 10 Cedarwood Road. Larry Mullen's childhood home (where the band was formed and used to rehearse in the kitchen) is at 60 Rosemount Avenue. They attended Mount Temple Comprehensive School on Malahide Road in Clontarf.
Bono lives on Vico Road in Killiney, which is accessible via the DART (Dublin Area Rapid Transit.) You can literally see the house from the train stop. He lives across from the Canadian ambassador to Ireland and his house is a tourist attraction; there is a wall of U2 graffiti beside it leading down to the beach and his gates are engraved (by him and his family) with personal symbols, etc. I've been a few times but am admittedly very leery about invading their privacy - I always wanted to meet him (which I did last year, eeeeeeeeek!!!) but I never want to do so outside the house 'cause it feels so invasive. If you go, I know you'll of course be discreet
I'll see if I can think of anything else!