The Irish commemorative stamps are quite interesting as they, to a large extent, depict the history of Ireland, her people, events and places. I highly recommend reviewing Jay M. Gregg's interesting treatise titled Postage Stamps Commemorating The Irish Struggle for Independence 1916-1923. His narrative is extremely well written and is a fascinating presentation of Irish history using stamps as his medium.
A very comprehensive bibliography of Irish philatelic literature is available on-line.
It is possible to subscribe to Irish new issues through the philatelic services of An Post, the Irish Post Office.