cheese shops in Dublin
Sheridan's is The Place but here's a link to another shop which gives some details of the products they stock: http://www.matthewscheesecellar.com/
And a link to the Irish Food Board which also lists a number of producers.
Whilst I'm sure you'll find good sheep's milk cheese there, in my experience, most non-cow cheese is goat rather than sheep. I assume from your posting history that you are probably American and therefore unlikely to be easily able to get Irish cheeses at home. Therefore, if I was you, I would look for the cow's milk product for which I think are the country's better products. Still, that gives you plenty of tasting opportunities.