We've been using the iPod with our old beige unit for several months now, and now we have a new iBook. (We have auto update off on both.) Now, are we going to have compatibility probs here? Are we good to go - just plug the iPod into the iBook and transfer songs? Aren't the tunes I'm getting from the Music Store a different format (AAC)? I'm a bit foggy on all this, and am in need to be enlightened. Thanks......