I don't put too much faith in their ranking system, but I must admit that it feels good that our book has shot up in the Amazon rankings. A few weeks ago, we were ranked in the #12,000 range, before the NDA dropped, we had moved up to about #4,000, and since the NDA drop, we've shot up to a whopping #1,404 in the overall ranking for all books (or thereabouts, it changes constantly). Nearly half the people visiting the Amazon page for our book are ordering it, and we're the #2 book in several relevant categories.
I have no idea what this means in terms of pre-orders, but it does give me the warm-fuzzies. Last time I checked, our book was the highest ranked of any of the iPhone SDK books, and the competition is not exactly lightweight. I'd be thrilled to even be running a close second to some of the other planned iPhone SDK books.
I'm hoping to have a publication date soon. The production side of the book has been on the back burner because of the NDA. Now that it's been lifted, we're in hurry-hurry-rush-rush mode, but I don't think the October 27th date is going to happen. Hopefully we won't miss by much, though. When I know more, I'll post more.
It's been a long haul, but the book has given me the opportunity to work with some really great people. Thanks to everyone who has offered their kind words of support (and those who e-mailed me that the NDA had been dropped).