A Reverse Telephone Lookup, commonly known as gray pages directory, criss-cross directory or reverse phone directory, is one of the most popular investigative searches on the Internet to collect customer details associated with telephone numbers.

With Reverse Phone Lookup, finding the name and address associated with landline phone number or, in case of a cell phone number, getting the name and billing address that's associated with the cellular number, have become extremely easy.

The technology is being used mainly to locate prank callers, keep tabs on unfaithful spouses or check on teenage children.

The Reverse Phone Lookup has become increasingly popular, so much so that the service has given birth to a number of 'Instant Search' Web sites that provide instant information about the customers. But there are some customers who did not get the information they wanted and have said that most of the time, the search provides inaccurate information. Five good Web sites,  known for their better service are listed below:

DocuSearch.com - Docusearch, called by Forbes.com Best of the Web, is America's premier provider of online investigative solutions. The Web site is known for its indispensable resources for any private investigator by providing information through a variety of searches like our phone number search, license plate lookup, SSN lookup and so on.

The Web site accesses information related to a reverse phone search for most of the U.S. They can trace the names and addresses of 10-digit landlines, cell phone numbers and pre-paid cell phones, only if the owner of the phone has registered it. The most interesting point about this site is that they follow the rule of no-hit, no-fee, that is, if they do not find the information associated with the number, they do not charge you for their service.

Docusearch.com has expanded their services and recently launched a forum to provide information about their Reverse Phone Number Lookup Search service and provide consumers with a full understanding of online investigative solutions before placing their order.

FreeReversePhoneLookup.info - FreeReversePhoneLookup.info launched its free reverse phone lookup information and report Web site on Oct. 23, 2011. While the free service of the Web site includes information about city, state and country, associated with the number, map visual of location and the phone type, paid service provides the owner's full name and exact address, owner's background information, details regarding household members, unlimited reverse phone lookup requests for any number, people search - to locate relatives, co-workers and classmates - and discounted reverse phone lookup and background reports.

The Web site received a huge number of positive responses from its users within a very short period of time and so it launched an online forum http://www.freereversephonelookup.info/forum/ on March 9, 2012, to help personal and professional phone number investigators connect with each other.  

WhitePagesinc.com - WhitePages, the leading provider of contact information for people and businesses in the U.S., includes the top 30 Web sites with over 30 million unique monthly users and it powers over 2 billion searches on over 1,500 sites, including MSN and the United States Postal Service. According to WhitePages, the Web site combines traditional directory services with new, innovative ways to connect to the customers. The site also offers a one-click access to more than 200 million customers. The company's suite of mobile products includes a top-50 mobile Web site and popular iPhone, Android, HP webOS and BlackBerry applications that have been downloaded more than 15 million times.

ReversePhoneLookup.org - ReversePhoneLookup.org is one of the most popular service providers. According to the company, they contain the Internet's largest database on hundreds of millions of phone numbers. To keep tabs on a loved one or to trace an unidentified cell phone number, the customer needs to simply enter the phone number and within seconds the Web site will return the results you need.

US-ReversePhoneLookup.com - With at least 200 million records in its database, the Phone Detective is another reputed company that helps you protect yourself from being scammed. This site provides services like unlimited reverse phone lookups for both landlines and other listed numbers, reconnect with friends, family and old co-workers, discounted cell phone and background reports, verify an address and all the while keeping your searches confidential.