There are the Jack Roberts booklets (review at http://www.megalithomania.com/show/review/27) as well as the Kenneth McNally tome, Standing Stones and Monuments of Early Ireland:
http://www.amazon.co.uk/exec/obidos/ASIN/0862812011/qid=1092075624/sr=1-1/ref=sr_1_8_1/026-3457825-3290844
both of which I used effectively during my Cork trip.