Gruber on iPhone and OS X
John Gruber just posted some dense information on the iPhone's 'OS X'. And while I'm at it, let me mention that those who thought the iPhone had an Intel CPU probably mixed that up. Jobs explicitly stated that the AppleTV had an Intel CPU, but was conspicuously silent on that aspect of the iPhone.
Gruber is pretty good with his guesses, so it might be an ARM or other RISC CPU, but I don't really care. OS X is very portable, and it used to run on Intel, PowerPC (RISC), Motorola 680x0... who knows whether it's an old CPU or they ported it to a new one? Though if it ran on a 680x0 again, that would be kinda cool :-)
I also agree with Gruber very much that the iPhone UI isn't going to be put on our Macs. It's a completely different set of requirements. However, I'm sure just like OS X progress bars ended up on the iPod, and FrontRow brought iPod-like navigation to the Mac, bits and pieces will start seeping into OS X. Maybe we'll eventually get pinchable touch-screens, we'll definitely get some of the graphic design (even if only in 3rd-party apps), but what makes sense will move over.
This'll be fun. I love implementing custom controls.
PS - Almost forgot: Rainer Brockerhoff also has lots of cool info on that topic. Also read the postings he made after that.