Matt,

There are castles and castle hotels. For the hotels & rentals I have a listing on my website: http://www.irelandyes.com/castles.html From there you can click through to each castle site. For castles that are not lodgings, try some of the links below. However, I doubt if there is one website that contains them all. There are lots and lots in Ireland.

http://www.castles-of-ireland.com/

http://www.castlesontheweb.com/search/Castle_Tours/Ireland/

http://www.castlesireland.com/

http://www.irelandseye.com/aarticles/travel/attractions/index.shtm

http://www.lookaroundireland.com/castlesofirelandpics.htm

There are also books about Irish castles.

Michele