The lights are on
The PlayStation Network will be undergoing maintenance tomorrow (Wednesday, September 25, 2013), but if you're smart and plan ahead, the inconvenience will be minimal. PlayStation Store, PlayStation Home, and Account Management will be down, but you should be able to play online.
In order to make sure your multiplayer is unaffected, you'll need to have logged in recently. A post on the official forums suggests that signing in during "the past few days" should put you in the clear, but for safety purposes, we'd recommend doing so today or tomorrow morning.
The maintenance is scheduled to begin at 10:15 AM Pacific/1:15 PM Eastern and last until 4:15 PM Pacific/7:15 PM Eastern. If you're planning on nabbing Rayman Origins for PlayStation Vita (coming to the Instant Game Collection today), we suggest starting that download as soon as possible.
[Source: PlayStation Forums]