PlayStation Network Scheduled Maintenance.
The Playstation Network might be down tonight or you may at least experience sign-in problems, MusterBuster from the Playstion Forums Europe warned;
PlayStation Network Scheduled Maintenance
Please be aware that the PlayStation Network will undergo scheduled maintenance today from 16:00 GMT.
During the maintenance, you will still be able to sign-in to the PlayStation Network provided that you have signed in recently. However, you may experience an unexpected sign out towards 21:00 tonight when we restart our systems. Also: Account Registration, Account Management and the PlayStation Store will be unavailable for the entirety of the maintenance.
Maintenance will take place between:
16:00 – 01:00 Tuesday 12th Jan – Wednesday 13th Jan
Sounds like you might still be able to play games online but the service won’t be stable. Shouldn’t be too much problem for the late night gamers in the states though.