This book has been around long enough that we've discussed it at length a few times before. As for the movie, many are proposed for each one that is made and released, but even if it were to reach the theaters I think I would pass on it.

The best things about it, in my opinion, are tied as much to the voice of the author as to the content of the story, and that voice can only be brought into the movie by voiceover narration - which should be used sparingly, if at all. Quite a few of the virtues of the book are in its digressions into side subjects and AT history and I can't see a natural way to bring these into the dialogue, either.

So, it would probably make a funny movie, but it would also be a substantial reduction of a very funny book.