There will be scheduled PSN Maintenance taking place on Thursday 1st March from 16:00 until 07:00 according to a post on the official PlayStation forums.
The maintenance will take place from 16.00 until 07:00 on March 1st and the following services will be unavailable:
PlayStation Store (PC and Console) Customer Account Management Account Registration
Users who are already signed into their account on PlayStation Network before the start of the maintenance will not be able to stay signed in to their online session and will be signed out at the start of the downtime period.
Users who attempt to log into their account after the maintenance begin will be presented with the site maintenance notification page.
PS HOME will also be unavailable for the duration of the maintenance.