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Each iphone needs its own mobileme account, I have the family plan with 4 iphones and you have to log into each one to view the find my iphone for that iphone.
 
It works, but you need to login to your MobileMe account on each phone and enable the "Find My Phone", none of the others need to be flipped on (mail, contacts, bookmarks).
 
Got it to work. Rebooted the phone that would now appear. Now both do.

However, I'm still unsure if location services needs to be on or off for this service to work.
 
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