Looking for information about a cellular number? Already tried the white pages and it didn't work? That's because cell phone numbers are unlisted! - Cellular numbers are unlisted which is why you can not find them on the white pages.
If you wanted information on a land number, then the white pages is the right place to go.
For mobile numbers however, the information is not freely available since it is considered personal information and there are privacy laws that protect the rights of wireless users.
How do you use a reverse cell phone directory? - It's a lot easier than using the whitepages and a lot faster too! All you have to do is copy the numbers you want to look up and to find a good database.
There are many to choose from.
Just plug in the numbers and in a matter of minutes you can obtain the information you need! What type of information could you retrieve? If you choose a 'good' service, it will provide you the following information:

• Cellular Phone Carrier and location of registration.
  
• Other telephone numbers he/she possesses
• Name and address of the owner with a map
• Relatives, associates, neighbors
• Previous residences/ addresses held by the phone owner.
  

How do I pick the right service? Is every service equally good? Very good question, glad you asked! Nope, every service is not equally good.
Because there is no official cell phone directory in the USA (because of the privacy laws, as mentioned earlier), different databases out there don't share the same information.
In other words, not all databases are equal in;

• Size
• Accuracy or
• how up-to-date they are

This is why you shouldn't pick any random service out there and instead use only the best databases.
Inferior databases may not have the number you're looking for or may only have outdated information regarding that number.