The late-night press conference Sony had this weekend informed us of their plans for bringing the PSN back online as well as how they were taken down to begin with, but they have yet to clarify the status of users' credit cards.
SCEA PR director Patrick Seybold responded to rumours that credit card information was not only leaked, but was being offered to be returned to Sony for a price, saying "to my knowledge there is no truth to this report of a list, or that Sony was offered an opportunity to purchase the list." No one is trying to extort Sony with any information that was possibly leaked, but whether there was a leak at all has yet to be 100% denied.
Once again Sony stresses not to give out any information to anyone who contacts you claiming they require your ID or other such information; Sony does not have anyone contacting PSN users and as such anyone who claims they are doing so are untrustworthy impersonators.