Originally it was suggested that the upcoming period of maintenance for the PlayStation Network would last around 12 hours on Easter Monday, but Sony has today confirmed in a statement that we can expect the downtime to be no longer than six hours.
Here's the skinny, from the PlayStation forums.
"We wanted to take a moment to inform you of a network maintenance, currently scheduled for Monday, April 21st from 5.30 PM to 11.30 PM BST, 9:50 AM to 3:50 PM Pacific Time (12:50 PM to 6:50 PM Eastern Time). We expect this maintenance to last approximately 6 hours.
If you’ve signed in to the network any time since April 16th you will be able to play games online and access partner apps such as Netflix during this maintenance period. The PlayStation Store, PlayStation Home and Account Management will not be available during this time, and users may receive a maintenance notification when attempting to access these services.
We thank you for your patience and support and apologize for any inconvenience this may cause."
There's currently a great Easter Sale going on via the PlayStation Store, so check that out and don't forget that you won't be able to download games during the maintenance period.