Hello there from not-so-sunny Ireland!
I am curious as to what is the general overview of Irish in Japan (if any at all?)? The reason I ask is that recently I was in An Siopa Leabhar in Dublin and chatting with the girl who works there, she said that recently they had had quite a few Japanese tourists in looking for learning materials! 🙂
As for online resources I would argue that there are quite a few good online resources however the websites usually are not decorated very well but a few which spring to mind are:
http://193.1.97.44/focloir/ – a fantastic resource for conjugating verbs
http://www.nualeargais.ie/gnag/gram.htm – a decent grammar resource especially for beginners and intermediate learners
http://www.abair.tcd.ie/ – an excellent tool for practising and listening to pronunciation. Of course, it is not always accurate and is computer generated based on a man’s voice/accent/intonation etc from the Meath Gaeltacht and another from Gweedore. I’d say that Meath one(Conamara) is of a higher quality and seems to be more clear but that might just be a personal opinion!
Anyway, my apologies if these have already been recommended and good luck in learning! 🙂