Shortly after firmware update 3.70 Sony follows up with downtime for PSN Maintenance.
The PlayStation Network will be going down for several hours tomorrow, apparently to undergo routine maintenance. During that time access to Account Management, and Registration will be down. Users may also experience trouble signing into the network for online gameplay and accessing the PlayStation Store. Maintenance on the North America PlayStation Network is scheduled to begin at 8am Pacific time (11am EST) and hopefully end at 7pm Pacific time (10pm EST).
The European Network will also undergo maintenance, and is scheduled from 4:05pm BST tomorrow until 02:00am BST on Friday 12 August 2011. Users will be unable to access the same services, but the European Blog also notes the PlayStation Store will be down, and you will be unable to sign into the European PlayStation Network’s website.