We use
www.openbook.org to search for for the string "new phone number" in peoples' status updates. I think we're able to search for that string even in friends-only updates, but that's completely different than being able to access a users phone number in the phone number field.
I don't have a problem with Facebook sharing any of my info. Anything that's truly private to me, I would never put on a social networking site. Maybe FB can finally make those white pages sites useful again, for things other than searching for old people to prank call.