And man, it is really hard to divorce the book from the movie. Moreso in this case than with many movies-and-books because I know I (and I suspect a lot of the rest of you) grew up with this movie from a very young age, with no familiarity with the book for a good long while, so the movie version is very much cemented in my brain.
So yeah, that being said, the main things that jump out at me so far are the ways that this differs from the movie. For starters - very abrupt opening! Although I prefer that to all the lead-in, the running-away-from-home, etc etc. Also no mean ol' biddy on a bike, or any of that nonsense. (I'll get you... and your little dog too!)
The slippers are silver, not ruby, the Good Witch of the North is rather different from the Glenda of the movies, Dorothy seems younger than was brought across on the screen, it's just "Aunt Em"... not that she gets much time anyhow... am I forgetting anything?
Other than the comparisons to the movie, well, there's not too much to get our teeth into yet! I think the abrupt opening works well, because otherwise it might give more of the impression of being a book about a Pioneer Girl a la Laura Ingalls Wilder or something, rather than a fantasy book. (Er, excuse me, modern-day fairy tale). I also like how all the magic stuff is so commonplace and not awe-inducing - I mean, Dorothy falls asleep while traveling in a cyclone, and doesn't bat much of an eye at a talking scarecrow for crying out loud!
Speaking of which, I am curious of just why the Scarecrow is sentient and all, but glancing at the picture for the next chapter opening I suspect we're going to find out a bit of his tale anyhow.
So. So far, so good. Not really too much to comment on yet, except for the "this is not quite the movie" aspects. We'll see how this continues next time!