A Dictionary of Irish Archeology.  Laurence Flanagan.  Barnes & Nobele Books.  Savage Maryland, 1992

The Discovery Programme of Ireland.
http://www.discoveryprogramme.ie/Research_Area/Content/TAR_SUR/TAR_SUR.htm

Mythical Ireland, Tara.
http://www.mythicalireland.com/ancientsites/tara/index.html

Stone Pages, an online guide to European megaliths and ancient sites.
http://www.stonepages.com/ireland/ireland.html