Sony has announced that unauthorized access of personal information has occured with the PC Playstation Store. They have stated that the issue of stolen credit card numbers is “very unlikely”, but that some users may find changed passwords and unauthorized account activity.
They have stated that they have taken immediate measures to rectify the issue and that system security has been restored. They will also be contacting anyone who has been possibly affected. Just to be sure, you should try to login to your account and verify that your password is still working.