Here's a link to a Washington Post article in which the author of Diary of a Wimpy Kid, series, Jeff Kinney says "I think a book still has a special kind of magic." I couldn't agree More Jeff.
It take heart that someone who has been so successful the blogosphere (Diary of a Wimpy Kid began as blog posts that now receive 70,000 hits a day) remains enamored with the written page. Interestingly, the series didn't appear as a book until after it's blog success and of course it has just been released as a movie.
When it comes to trying to predict the future of children's books, it seems to me, that if you give kids something they can relate to, they'll eat it up with a spoon, no matter what the format. Just keep that in mind all you kid's writers, illustrators and publishers out there.