I took ten lessons from my Irish club, followed up with
the Ceolta na Si CD, now I copy lessons from the Erins
Web site, augmented with watching Ros na Run, the Irish
soap with subtitles that I'm lucky enough to get on public TV.

I love the lessons, they introduce new concepts gently.
There are occasional typo's, which is no big deal, but
my question: some pronunciation is quite different from
what I learned (and my Focloir Poca seems to agree with
me), but are these regional differences and thus both
correct, or not?

Erins Web Mine

agam through acu - accent 1st
syllable vs. 2nd syllable

dh - they say 'guhrus' vs. yoras

iontach - oontach vs. intach or eentach

ag eiri - eyeree vs. ayree

tuirseach - toor vs tir

cad e mar ta tu fein - fane vs. hane

raibh - rev vs row

le do thoid - hil vs hull

go deimhin - dye-in vs devin

Go raibh maith agat, a chairde

I seem to recall that those lessons in 'Erins Web' were taken from weekly tutorials in "The Irish Reader." As I remember it, they are of standard grammar and Munster pronunciation. So, I guess the short answer to your question is - yes, it is a regional difference.