A reverse telephone number search uses a phone number to search for a person or company. It is called "reverse," because the search is the reverse of a typical search where you search a name to find a phone number. A reverse number search can help you determine the owner of a phone number, which is useful when researching your caller ID log to determine who's call you missed or the identify of a frequent, harassing caller.
Check out Addresses.com and look for their "Reverse Phone Lookup" on the top right side of the page. In additional to the site's usual People Search and Email Lookup services, you can search for a person based on the phone number. This is a free service that does not force you to purchase anything to obtain the name and address of the phone number's owner.
Navigate to the YP.com site to locate the name and address from a phone number. Just click "By Phone Number" at the top and enter the phone number in question. Like Addresses.com, this is a free service.
Visit WhitePages.com and click on "Reverse Phone" at the top. Enter a phone number to try a reverse search. The results are less useful, since they will only tell you if there is an entry available for purchase.