White Rabbit Press has some Japanese Graded Readers for the iPad. As of this writing there are 9 of them with three more “coming soon”. They are graded according to the JLPT (Japanese Language Proficiency Test) level that they are meant to accompany.
I downloaded the first one, which is at level 0 (JLPT level 5) and it is definitely easy reading. It is in Kanji with furigana. In case you’re wondering, it is a six page children’s story telling the fable of the grasshopper and the ant. Each page has a picture as well as text, and the text has a lot of repetition in it.
However, each text is also read aloud by a professional voice actor and native speaker and, on the first book, she actually does a really great job.
The download was $2.99 in the app store. You’ll have to decide for yourself if that’s a good price or not. Opinion on that point seems mixed in some of the reviews I’ve read.
If you go to the website you can check out a free demo and see what you get. At the very least, depending on you language level, it’s worth a look.