Apple just needs to offer something that Facebook would value: give Facebook native integration in iOS and the social network will never be beat by any of its emerging rivals.
It's clear that Apple's iOS will lead the next phase in personal computer history. If Facebook is allowed to piggy back on it and Apple is able to piggy back on Facebook's success, both will win.
I like that idea.
I also like Ping, and am sure I'll like it even more with FB integration.