The first lawsuit against Sony's recent security breach has been filed today in the U.S. District Court of California on behalf of Kristopher Johns. Even though the terms and conditions specifically state that Sony is not liable for any loss of data, Sony was sued for not taking reasonable care to protect, encrypt, and secure the private and sensitive data of its users, and for not warning clients that their data has been compromised in time for them to take effective action.
As stated before we recommend you change all email passwords that are connected with any PSN accounts and take any neccesary measures to protect your Visa infromation.