Just one day after writing the initial post, we have a lot more information about CarPlay, Apple's iOS in the car initiative.
The above video is a demo specifically for Ferrari. There are other demos floating around for Mercedes and Volvo. In case you were not planning to spend $100,000 for your next car, don't worry. Ford, Chevy, and the rest of the usual suspects are also going to be getting the CarPlay treatment later this year. Of the videos floating around, this one is the best. An Apple rep demonstrates the features.
Don't make the mistake of thinking this is the one, true way that CarPlay will work. It is not. Some companies will use touch screens, some dials, some buttons. Some will use a mixture of the three. This first implementation seems to be using the lightning cable. But I believe wireless is also possible. It all depends on the car manufacturer. The applications may be Apple's, but the experience is partially dictated by each manufacturer. No two are exactly the same.
Wile CarPlay is exclusive to Apple, the in-dash system will still work without an iPhone. It just will not provide the CarPlay experience. Everyone else will just default to the standard entertainment system of that particular car. The Apple experience only presents itself when the user connects an iPhone and activates CarPlay with the press of a dedicated button. If Android users want an experience particular to their device, they will have to wait for Google who is currently in the process of kirfing one up.