Certain online websites are useful for doing reverse phone number searches for free. Many websites offer paid reverse phone number searches, which can be helpful if the free websites don't have the information.
Some online reverse phone number searches might not have information about cell phones, but searching through certain social networking sites might produce results since some members have their cellphone numbers listed. To do this, just enter the phone number with the area code in the search box at the top of the page. If a profile with a matching phone number is on the website, it will show that person's page.