Or maybe someone is prank calling you and you want them to stop. Perhaps a telemarketer won't stop calling despite your pleas to be left alone. Or maybe you suspect your husband and wife is cheating and you see a

strange number on his or her cell phone.

Whatever your reason may be, you will most likely end up using a reverse phone number lookup service. These paid services can research any telephone number and provide you with a full phone report including the owner's name, address, connection status, type of phone line, and other details.

But before you spend money on these services let me tell you about a free method for looking up phone numbers. Just go to Google, Yahoo, or MSN, enter the telephone number, and click "search".

You may have to experiment a bit to get the right results. Try entering the number both in quotes and out of quotes, and try different number formats including:

777-777-7777

7777777777

(777)777-7777

While this method is free, it is not the most reliable. You have to hope that the owner posted his or her number somewhere on a website, forum, or blog such as MySpace. Also, keep in mind that the results are not guaranteed and could be outdated or outright incorrect.

Of course, it can't hurt to try since it's not costing you anything.

But if you strike out with the search engine method, your best bet is a reverse phone number lookup service. While they aren't free, the cost is pretty fair for the amount of information provided and the time saved. It

would cost hundreds of dollars to pay a private investigator to collect all of the information in a typical phone report, but online services can offer you the same detailed information for around $14 per number. Also, some services will let you pay a one-time fee (usually around $39-59) for the right to run as many phone number searches as you want.

Why do they charge for the lookup service? Well first of all that's their business. If you were able to provide such a valuable service would you just give it away?

Also, the lookup services themselves are charged for each search they run. This is because their searches involve submitting a query to the databases of various telephone companies and cell phone carriers. The carriers charge the lookup service a fee each time the need to access the database for a search, so the lookup service has to pass along the cost to you. If they didn't they'd quickly find themselves out of business.

For this reason, there is no such thing as a free reverse phone number lookup service. They just don't exist. And if you see a lookup service promising "free" results, use caution. They are either using deceptive marketing to lure you in or they are teasing you with a free search in hopes that you'll pay for another of their services.