The PSN will perform its routine maintenance beginning tomorrow afternoon of June 25th. The maintenance is scheduled to start at 9:30AM PT through 4PM PT.
During the maintenance, the following services will not be available: the PlayStation Store, PlayStation Home, and account management. As for its online play and apps provided will still be available, assuming that you have signed in to the network at some point between today and before the maintenance. Those who wishes to play online should definitely sign on today.
Hopefully after the maintenance, we should see the PlayStation Store updates.