If you haven't heard, the four major credit bureaus have agreed to release personal information about anyone to any tom, dick, harry or Jane.  This was agreed 1 July 2001

Unless you "opt out".  Call
1-888-567-8688
Listen to the prompts.  By selecting number 3, you will opt out permently.  You can also opt out for other family members by waiting till the end and follow the prompts for other people.  

I took care of my family today, don't want no stinking soliciter or statician or AARP or HCI or Rosie O'Donnell flunkie, calling me for my generous donation.

I'VE GOT A DONATION FOR THEM...........
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Thank you for the info and the number pakrat. There has been a federal law for some time that states one needs written authorization in order to access (check) your credit. However, several companies either ignore this or circumvent it.
While this may not sound like a big deal you should know that each time your credit rating is checked it lowers your score from five (5) to ten (10) points. This might not concern you until you apply for a major loan such as for a home and learn that your score is too low to qualify as a result of your score being checked repeatedly. Every time you get one of those pre-approved credit card applications in mail? Well, they ran your score, in violation of federal law, and knocked you down five or more points to make that offer. Still wanna take out that card with all of the wonderful low interest, no fee features?

Actually, unsolicited inquiries are kept separate from 'authorized' inquiries.  They do not affect your score nor are they shown to a creditor that is obtaining your report at your direction.  This is straight off the verbage printed on my actual credit reports...

Here's the government website on it.  http://www.ftc.gov/privacy/protect.htm

Actually, gunslinger, the Credit cards soliciations that you get in the mail usually aren't as a result of a direct credit check.  What usually happens is that a company (let's say JoJoBank) decides it wants to spam a bunch of folks in its local area that it's offering credit cards.  They only want to target a certain range of folks with decent credit histories.  They call up (insert your favorite bureau here) and pay for a list of names and addresses that meet the criteria they are looking for.  They don't run a credit check directly on you...they have the credit bureau find a list of folks who meet certain criteria, and use that information to send out the offers.
Now when you actually apply for the card, you generally will find a line on the app that says you authorize JoJoBank to run a credit report on you, and this would be an actual inquiry that would get listed on your report.