Update 2: PSN seems to be coming back up now. People are reporting being able to download from the store.
Update: According to Sony, current indications are that it’ll be restoring PlayStation Network services in approx. two hours.
Original: If you are currently trying to sign into PSN but can’t then don’t worry, because the service is currently down for everyone.
According to the SCEE twitter account, Sony is aware of the problem and is working with the technicians to find out when it will be restored.
We will update you when we know more.