The latest information on the PlayStation Network service outage
The ongoing outage of the PSN was caused by "external intrusion" so far this was already known. But seems the "hackers" got your personal data as well, or maybe, well sony dont know exactly which should worry you.
According to Sony UK this data was accessed and maybe copied:
PSN/Qriocity security question and answer
"While there is no evidence that credit card data was taken at this time, we cannot rule out the possibility. If you have provided your credit card data through PlayStation Network or Qriocity, to be on the safe side we are advising that your credit card number (excluding security code) and expiration date may also have been obtained."