If you're looking for language courses, you might check with Acadamh na hOllscolaíochta Gaeilge:
http://www.acadamh.oegaillimh.ie/ I know they run 5-week programs in the summer, for which university credit is available. I don't know if you have to be a university student to enroll in these, or if they're open to the public.
Or if you just want to visit the Gaeltacht, roam around on your own and hear/speak some Irish "in the wild", that's an option too. I did that earlier this month and had a lovely time.
This site maintains a list of B&Bs, guesthouses, etc. where Irish is spoken:
http://www.gaelsaoire.ie/