Does an official mobile phone directory exist? Unfortunately, the answer is no...a mobile phone directory does not exist. This does not mean you cannot type in a person's name into Google or another favorite search engine, hit Enter, and find out cell phone information related to that person. If, for example, a person had placed an online ad or posted a Facebook or MySpace page where they included their mobile phone number, you will strike pay dirt. Of course, how much information you receive depends on how much other information they provided. But it's certainly worth a try.

Plus there are some volunteer mobile phone directories where people have deliberately posted their cell phone numbers, but most people have not done that nor will most people be likely to. After all, who needs to be called by telemarketers.

Even a proposed joint cell phone directory the development of which has been endorsed by the major mobile phone carriers will require that cell phone users opt in, and it will not be published like a regular telephone book. Indeed, it may not even be posted online.

So what does someone do when they want to find someone's cell phone number? Well, the first thing to do...if searching does not work...is to actually ask the person for their phone number! It's far and away the easiest way to get someone's mobile phone number. If they do not want to give it to you, then you should probably respect that and stop asking. On the other hand, you may have a genuine reason for looking. If so, ask a mutual friend.

If that's not an option and you have a reason considered legitimate by the Driver's Privacy Protection Act (DPPA), contact the Department of Motor Vehicles in the state where the person lives and make a formal request. That's simply a matter of filling out a form, swearing to the legitimacy for your request, and paying a small fee. The person's phone number should be part of their DMV record.

Or you could always hire a private investigator. This is an expensive option, but it is likely to be successful in finding a person's mobile phone number.