Currently Being ModeratedJan 8, 2012 7:36 PM (in response to antoniofromsalisbury)
The two devices are using the same iCloud ID, hence they are syncing the contacts, as the system is designed to do.
BTY, I'm not sure what your intention was to install the Find My iPhone app, but if you are trying to start that service, the app won't help. It is intended to locate OTHER devices. To start the Find My iPhone service, you do it via the settings.