I felt I had to share this as I use Vicipéid everyday. The Irish language Wikipedia has helped me learn a lot of Irish (e.g. countries, place names, grammar etc.) and editing it I feel helped the language to grow.
The link to Vicipéid (Irish Wikipedia) is: https://ga.wikipedia.org/wiki/Pr%C3%ADomhleathanach
Wikipedia is a great place for any language! I'd recommend first trying to read articles on subjects you're vaguely familiar with (or quickly read about them on Simple English wiki before proceeding) so you can deduct the meaning of new words from context rather than checking the dictionary all the time. :)
You know I'm wondering if some children series or books have been translated into Irish. Like Junie B. Jones or The magic Tree House series. Those would be a great source for learning Irish!
I know you can get Irish translations of The Hobbit and Harry Potter and the Philosopher's Stone at least on Amazon. I'm sure there is more out there too!
Don't use Harry Potter, though. It's translated at roughly the level of a Masters in Irish. Even native speakers find it difficult.
Really? Yikes! O__o well I guess it'll be the ultimate test to prove if I've mastered the language then, haha.
There's some great native Irish books out there - classics plus new publications. My mother is friends with an illustrator who's been working for one of the publishers of new picture books, so she has got us a few of them.