Their web site is here and the TripAdvisor reviews are here. Their wikipedia site is here.
The line to kiss the Blarney Stone was too long but we enjoyed the caves and gardens on the grounds.
There is a fascinating legend regarding the actual Blarney Stone. A wikipedia article suggests that Robert the Bruce of Scotland gave a portion of the Stone of Scone to the king of Ireland who then put it into Blarney Castle.
Another tradition holds that, in gratitude for Irish support at the battle of Bannockburn (1314), Robert the Bruce gave a portion of the stone to Cormac McCarthy, king of Munster. Installed at McCarthy's stronghold, Blarney Castle, it became the Blarney Stone.