Here is a great resource for Irish Genealogy. This is database of Irish Immigrations form the Boston Pilot hosted by Boston College ( http://infowanted.bc.edu/ ). Since they explain well, here is a quote from their website:

From October 1831 through October 1921, the Boston Pilot newspaper printed a “Missing Friends” column with advertisements from people looking for “lost” friends and relatives who had emigrated from Ireland to the United States. This extraordinary collection of 31,981 records is available here as a searchable online database, which contains a text record for each ad that appeared in the Pilot.

The advertisements contain the ordinary but revealing details about the missing person’s life: the county and parish of their birth, when they left Ireland, the believed port of arrival in North America, their occupation, and a range of other personal information. Some records may have as many as 50 different data fields, while others may offer only a few details. The people who placed ads were often anxious family members in Ireland, or the wives, siblings, or parents of men who followed construction jobs on railroads or canals.

I’d like to thank the Looking4Kin blog for bringing this to my attention:
http://looking4kin.blogspot.com/2009/06/2-great-sites.html