There is no existence of an online cell phone directory service.  But if one does type the number on the search engines one could find the number of times the number appears on the search results.  There are not much people who use this technique.  Apart from this there are several volunteer cell phone directories that are popping up and gaining popularity.  These cell phone directory sites initially collect the details of the person who is searching and then gives the right to search for other cell phone numbers.  The reverse lookup cell phone number service is the only way that allows finding out the owner of a cell phone number.  One should find the right lookup service that has a large directory.  This directory should be holding all numbers and addresses up-to-date.  This should also be containing information about their past and present living history.  If all these information is provided the search that is made would be worth enough.