Sony has announced that there will be some more maintenance for the PlayStation Network.
The maintenance begins on Thursday 27th July at 16:00 BST, lasting until 8:00 on Friday 28th July. While this occurs you won’t be able to access the PlayStation Store from the PS3, Vita or PSP. Account Management and Account Registration will also be unavailable. Online Play will also be affected, but if you are logged in before the maintenance begins you will be able to stay online.
Source: PlayStation Blog