Hi,
Well, there are basically two ways for a non-EU citizen get into Ireland to work, the Work Permit (WP) or the Work Authorization (WA). Each one has its own set of rules and regulations.
Check out the Department of Enterprise, Trade & Employment (DETE) website as they have the rules for both.
www.entemp.ie They are located in Dublin.
The WA is set up for a certain group of people whom Ireland has deemed particularly necessary to its workforce and who are in high demand. These positions are highly-skilled with specific expertise in pre-chosen fields. Currently, those jobs that are considered to be under-staffed here in Ireland are Dr, nurses, engineers, town planners, IT professionals(though the IT chose has certain criteria of its own that must be met). These work authorizations are given on a two-year basis and are applied for at your local Irish embassy. They give job mobitily in that you can change employers as long as you stay in the same sector of work, ie. a DR. in Cork moving to work as a Dr. in Dublin. I've heard that they do not have as long as a waiting period as the WP option.
The WP is a more difficult route. Basically, you have to find an employer who will hire you before you can come over here to work. And there is a list of jobs that are a WP will NOT be issued for (restaurant, bar, housekeeping, construction....). Check out the DETE for the full list.
The WP application must be completed by your prospective employer as well as payng the application fee (currently 500 Euro per year). You must wait to have the WP approved, you cannot work will your application is in process (takes about 8 weeks). The employer must first register the job position with FAS (the Irish employment people) for 4 weeks in order to offer the job to any Irish citizen, then any EU citizen before offering it to you. The employer must then get a letter from FAS stating that all avenues were tried before offering the position to a non-EU person. They really have to prove that you and you alone are the one for the job! You cannot change jobs once you have a WP for a specific employer, if you want to change employers, you must repeat the process from scratch. So, basically, find a job, then wait up to 12 weeks before you can start! Easy eh?
The Irish immigration system has really tightened here over the past few years and the press insist on calling a Work Permit something for 'lower-skilled' or 'un-skilled' workers which really gets my blood pressure up! A lot of us are on the WP scheme and believe me we are not un-skilled!!
Anyway, the system is not easy by any means, but do-able if you put your mind to it & research your options. Really, check out the DETE website for the full details and paperwork requirements. And start checking out your family past, you're from the States, thought all you guys had Irish grandparents!

If you have an Irish granny you may be able to get Irish citizenship & then you can hop on a plane and be here enjoying a sweet pint in no time! The Dept. of Justice handle citizenship, in case you're interested.
Good luck, try at least, nothing to lose!
Regards,
Maria