Place the contents of your wallet on a photocopy machine, do both sides of each license, credit card, etc., you will know what you had in your wallet and all of the account numbers and phone numbers to call and cancel. Keep the photocopy in a safe place. 

We've all heard horror stories about fraud that's committed in your  name, address, SS#, credit, etc. Unfortunately I (the author of this piece who happens to be an  attorney) have first hand knowledge, because my wallet was stolen last  month and within a week the thieve(s) ordered an expensive monthly cell  phone package, applied for a VISA credit card, had a credit line approved  to buy a Gateway computer, received a PIN number from DMV to change my  driving record information online, and more. 

But here's some critical information to limit the damage in case this  happens to you or someone you know.  As everyone always advises, cancel  your credit cards immediately, but the key is having the toll free numbers  and your card numbers handy so you know whom to call. Keep those where you  can find them easily. 

File a police report immediately in the jurisdiction  where it was stolen, this proves to credit providers you were diligent, and  is a first step toward an investigation (if there ever is one). But here's  what is perhaps most important: (I never ever thought to do this) - Call the three national credit reporting organizations immediately  to place a fraud alert on your name and SS#. 

I had never heard of doing  that until advised by a bank that called to tell me an application for  credit was made over the Internet in my name. The alert means any company  that checks your credit knows your information was stolen and they have to  contact you by phone to authorize new credit. By the time I was advised to  do this, almost 2 weeks after the theft, all the damage had been done. 

There are records of all the credit checks initiated by the thieves'  purchases, none of which I knew about before placing the alert. Since then,  no additional damage has been done, and the thieves threw my wallet away  this weekend (someone turned it in). It seems to have stopped them in their tracks. 

The numbers are:

Equifax: 1-800-525-6285 
Experian (formerly TRW):  1-888-397-3742 
Trans Union: 1-800-680-7289 
Social Security Administration (fraud line): 1-800-269-0271