A friend sent me this checklist from the Telegraph on how to protect your identity online
1. Change your passwords
Many people use the same password for multiple websites. If you entered a Sony Pictures contest with a password that you use on other sites then it is essential that you change it as soon as possible. Go to the website concerned then login and look for an option to change your account details. Choose a new, secure password.
2. Look out for fraudulent emails
If the hackers have your email address, one thing they are likely to try is a 'phishing' attack - sending an email purporting to be from a bank or ecommerce site asking for your details. View any such email with suspicion and do not follow links from emails that ask you to provide personal information. If you are particularly concerned then you might want to consider changing your email address.
3. Be alert for suspicious phone calls
If your phone number was among the details you submitted to Sony Pictures then it might be used by fraudsters attempting to sell you services or trick you into buying things that you don't need. Treat any unsolicited calls with suspicion.
4. Monitor your bank account
Though there is no evidence that bank or credit card details was stolen in this attack, much of the compromised data could be used for identity theft. Keep a close eye on your bank account and check any payments that you don't recognise.
5. Consider an ID fraud monitoring service
If you're concerned about the possibility of identity theft then you could register for an ID fraud monitoring service. These services will look for credit checks against your name, such as those carried out when a credit card account is opened or when a loan application is made, and will warn you when they occur. Typically, this protection will cost a few pounds a month.