Sorcha, I was given more information than I could possibly have used this summer, when I was preparing for an August trip to England and Ireland (one week each).

If I had my own PC and my cookie, I could give you links to the thread I originated and a couple of concurrent threads on places to go and people to see in Ireland. (One was Dublin-only -- may have been entitled "Real Dublin Sessions Please?"). If you're able to search it out, maybe you can find some useful references under the thread title "England/Ireland in August: Advice?" Some of the posts include cross-references to other threads.

Can't really add much from my experience: we only spent one day in Dublin, and never got off the beaten track there. (We did have some interesting and unique encounters further west.) I wouldn't imagine your friend needs me to direct him to the Temple Bar area.