As for the process of interviewing: for a lot of the more interesting jobs at Apple, interviewing involves signing an NDA. Hence, whether or not they end up getting hired, they’re contractually prevented from talking about the interview process.
Having worked there in the past myself but not anymore, I can speak only _somewhat_ freely about it all. The interview process can be intense, taking up to several weeks and with a minimum of 4 interviews, but usually 7 or 8. Often, for practicality reasons (travel to Cupertino), all those interviews are done in a single day, and if it's more than 8 it'll be done across two+ days. As for the specifics of an average interview itself, I can’t really say anything.
And as for working there, my own experience was largely fantastic, but it wasn't for me in the end. Apple's campus is by far the nicest I've seen of all the major companies (and I've seen all the ones in Silicon Valley), and though there is always a constant pressure, stress and a major (and insane) deadline to make, working there is incredibly satisfying. Unless, perhaps, you're at MobileMe. But maybe that was just me.