But keep in mind none of this is new, since the same API's have been around on the Mac for a very long time. Anyone freaking out because it does so on a smartphone should hide under a rock and shut the hell up.
Actually, it is new. As I touched on in my previous post, the iPhone has a single C function that returns the device's phone number. It is completely unrelated to the Address Book API, which does let you access the "me" record, if it's available. To be specific, the function is in the CoreTelephony framework, which is not a part of Mac OS X.