There's a Bob Books app (or two) that are better than the books. The pages start out black and white, but as you spell the words for items on the page, they get colored in. There are settings to change the difficulty. I think in the first setting you can drag and drop letters in any order. In the second setting, you have to go from left to right. In the third setting, the letters no longer appear at the target location. It's phonics based, so I don't think the letter names are ever used.
On the downside, the app samples all the stories, pulling a page from here and a page from there... so the app itself doesn't tell a story.
I wish starfall would port the "learn to read" section of the website, instead of just the alphabet part.
