This is the site that enabled me to remove the footing that sent my McGarr, “brick wall” tumbling, (like that metaphor?) http://www.rootsireland.ie/
The first page is where you log in or register, which is free. You can then perform a search for baptisms, marriages and a limited number of deaths. There is also Griffiths Valuation, though given a choice I would use the following site for Griffiths-- http://www.askaboutireland.ie/griffith-valuation/
The Foundation's site allows a search of a specific county, or you can opt for an all Ireland search. To search all Ireland simply fill in a name. The results, sorted by event will appear below the search box. By clicking on one of the “view” tabs an advanced search box will open allowing you to narrow the search. To perform a specific county search, instead of filling in a name, go to the sidebar which contains a link to the genealogy centers available. Before you fill in the search box that appears after you choose a center, click on the view button next to the event you’re searching for and the advanced search box will open up. You can then enter more specific terms such as parent’s names or a parish if you know them. Both options allow you to limit the years searched.
The rules have changed since I first started using the site, it now costs 1 credit to see the hits your search produces, but you are given 10 free page views when you register and more every time you purchase a record. The search results page will give you only a first and last name as spelled in the record and the year and county of the event, it will not give you a parish, so if you already know those details, don’t bother using your free credits to view it. You will have to view it however if you wish to purchase the actual register transcription which will give a year, parish, parents and sponsors or witnesses and will cost you 25 credits, or 5 Euros.
You can, through a process of elimination, find the year at no charge. It’s also possible to find the parish by a trial and error search of each parish in the county, though that option requires a first name so you must either know the name or get some possibilities by viewing the results page. It doesn’t take long to search the various parishes, especially if you know whether the family was Catholic or Church of Ireland which are clearly labeled, (I hate when sites don’t tell you which denomination you’re looking at).
If for example you are searching for all the children of one couple, you would fill in the parent’s names and only the last name for the child. Looking at the search results page will then give you the first names of children with those parents. Now you have first names you can begin searching by parish which may help you decide if this is indeed your family. That 5 Euros a crack can add up, you don't want to purchase the wrong family records!
If you know the child’s name but not the parents or only one parent, I’ve found you can often guess the names of parents in the baptismal records without going to the expense of buying the record. After all, the given names in use at the time were quite few; most of my male ancestors were James, John, Edward, Michael, Patrick or Daniel, the females all seem to be Mary, Anne, Ellen or Catherine. Unfortunately this won’t get you the maiden name of the mother, or the names of sponsors which can be handy to have. I wound up buying all the McGarr records I could find because I was desperate after years of being unable to find even a mention of them.
While searching, remember, not all early marriage records gave the parent’s names, or sometimes only the father’s, so if you include parents names the search engine goes out looking for them and comes up empty even though the record is there. Try searching with and without them. Ditto baptisms, sometimes only the father was named.
Another tip, the site is very picky about spelling. For instance, in one search when I typed Honora for a first name I got zero hits, but typing Honor produced the one I needed, same with Anne and Ann, and Mary and Maria. Spelling was not as precise back then either, surnames got spelled in myriad ways, and the search engine will catch some variations but not all, so try different spellings for first and last names.
To sum it up use some caution, don’t whip out that credit card too soon. Use the free searches and play with it ‘til you get the feel of how it works. Happy Hunting.