Sony just announced that the PlayStation Network is going down tomorrow, Tuesday June 25th for maintenance. The maintenance will last for 6 hours, from 9:30 am PT to 4:00 pm PT.
Sony states that “While the PlayStation Store, PlayStation Home and Account Management will not be available during the maintenance period… you will be able to access online play and apps provided that you have signed in to the Network at some point between now and the time of the maintenance.”
That means that you should go online right now, and you will be fine tomorrow. Good luck!