Sony has revealed that the PlayStation Network will be down the whole day tomorrow (Monday) starting at approximately 6:00 a.m. PDT/9:00 a.m. EDT and will last an estimated 13 hours, concluding at 7:00 p.m. PDT/10:00 p.m. EDT.
During this scheduled maintenance, people won’t be able to access the PSN Store, PlayStation Home. manage their PSN accounts or play online — in short, you have to contend with your PS3 being an offline system for 13 hours.
While it’s never fun to be left out of online multiplayer for long, just know that Sony is doing this for your best interest…that, or they have a new firmware update coming again soon.
Source: Official US PlayStation Blog