The Irish Manuscripts Commission has a lot of old Irish books online and free. These include the Calendar of Ormond Deeds, The Book of Survey & Distribution and The Civil Survey and many other interesting books that could be useful for genealogy in early periods. They plan to add more titles.
There are nearly 350 eBooks listed at this site with links. Most are 19th century with some from the previous century.
On this site the eBooks are grouped under the following headings:
* History of Ireland* Local History* Guidebooks* Irish Diaspora – General* Irish Diaspora- North America* Family Histories* Disputed Inheritance Cases* Irish-American Family Histories* Irish-Canadian Family Histories* Irish Genealogy Sources
County Tipperary Roman Catholic Records at Rootsweb lists the Co Tipperary Civil Parish name and next to it the Roman Catholic Parish name and when the parish began. This makes tracking ancestors in Co Tipperary a little easier.