Hi Ahmed,
Unfortunately, there is no way to sort out IP Phone search based on registration status via the CUCM Admin Page. I verified in CUCM 8.0 as well. You can put in a feature request for the same to your Cisco Accounts Team.
Having said that, you can get what you want via the RTMT tool. Here is how to go about it:
++ Launch RTMT.
++ Go to CallManager --> Device.
++ You coule either do a device search or phone summary to give you what you need.
HTH.
--
Harmit.