Irish to America Online (New York)|
The National Archives has added the Irish Famine Immigrants database to their website for free searching. This covers Irish arrivals to the port of New York for the years 1846-1851. You can begin your search here...
Books: The Famine Immigrants: Lists of Irish Immigrants Arriving at the Port of New York, 1846-1851 edited by Ira A. Glazier and Michael Tepper; Baltimore: Genealogical Publishing Company, 1983-1986
These books index Irish passengers who arrived in New York between 1846 and 1851
Some of the volumes may still be in print - click on a volume number for ordering information. You might also find them at some genealogy or public libraries.