As Lughaidh is always lamenting, there isn't really a full course for authentic Ulster dialect, mostly just standard Irish with a few token Ulster features. You can always ask Lughaidh here to fill you in on the Gaoth Dobhair Gaeltacht version of Ulster Irish.
For Munster Irish, there is the old Teach Yourself Irish by Myles Dillon/Donncha Ó Cróinín which is out of print but there are instructions on how to download the text in .pdf format and the sound files
here: and a study group going through it
here though I think they may actually be working through
Séadna together instead at the moment with excellent supplementary notes by An Lon Dubh.
For Connemara Irish, especially Cois Fhairrge dialect, try Learning Irish and follow the Connemara content here.
For something more standard, Buntús Cainte is great for general pronunciation and conversation.
Whichever dialect or course you choose, you can always ask for comparisons with other dialects and with the standard here at Irish Language Forum.
PS: Most of the "arguments" about dialects come from non-natives who don't know much outside the standard or whatever dialect they learned first. We aim for dialect awareness here - learn to recognise the features of other dialects passively but concentrate on using the forms particular to whichever dialect you choose. If you are studying for exams, though, you'll also need to be able to convert the forms to standard (CO).