As soon as you suspect your ID has been stolen you can take action to stop unauthorized charges and start to recover your identity.

• Place a fraud alert. If you suspect fraud, place a fraud alert with each of the credit reporting companies: Equifax, Experian and TransUnion. The alert notifies creditors that you have been a victim of fraud and lets them know to verify that you are actually making new credit requests in your name. Placing a fraud alert does not affect your credit score.
• Contact fraud departments. For each business and credit card company where you think an account was opened or charged without your knowledge, contact its fraud department. While you are not responsible for fraudulent charges to an account, you need to report the suspicious activity promptly.
• Freeze your credit. If you want to stop anyone from opening credit and requesting loans and services in your name without your permission, you can freeze your credit. You will need to request a freeze with each of the three credit reporting companies, which again are Equifax, Experian and TransUnion. To apply for new credit, you need to unfreeze your credit, again, through each of the credit reporting companies. You can either request a temporary lift of the freeze or unfreeze it permanently.
• Document everything. Keep copies of all documents and expenses and records of your conversations about the theft.
• Create a recovery plan. The Federal Trade Commission has a valuable tool that helps you report identity theft and recover your identity through a personal recovery plan.

Source: CNET.com