Further, Gresham promises the movie will again be very faithful to the original source material, and discusses the possibility for a few more movies and what order said movies would be filmed in. Essentially, the natural order dictates the filming order. That is to say, they've already started with these kids, so they'll go ahead and film the books which include these kids (excluding Last Battle, presumably). So we're looking at a Dawn Treader film, and likely Silver Chair after that, to follow the Eustace thread. So really, we're getting books 1-4 in the original order, for those of you following along at home. If you own any recent set of Narnia books you may be confused, but that's because the books were rearranged into chronological order eventually. Lewis may have been quite fine with this, but I personally am very glad the movies are being shot in original order, and feel the choice says something about the value of reading the books in that order. If Magician's Nephew was really the best story to introduce the Narnia world with, don't you think the filmmakers would have gone there to start? Yeah, me too.
There's quite a bit more worthwhile and enjoyable information in the interview which we didn't touch on in this post. Go ahead and have a read.