Useful genealogy sources:
O’Gara surname specific
RootsWeb Discussion List
Subscribe for regular updates of simply search the archives.
O’Gara Message Board: Ancestry.Com
Similar to Rootsweb, more advanced information requires fee.
O’Gara DNA Project
Ongoing DNA project tracing various roots of the O’Gara clan (fee required).
Forum for research & sharing O’Gara genealogy information.
Where they are now may help you find out where they’ve been!
General Information Sources
National Archives of Ireland
1901 and 1911 Census records online.
Irish Government site indexing church records, a few O’Garas listed.
Excellent site for starting your search.
Another excellent site
US Citizenship and Immigration Services -Genealogy
USCIS offers name search and copying services (nominal fee).
London based free genealogy service for the UK and Ireland
National Library of Australia eResources
Australian database access for Australian residents with a library card.