I just now logged in... No maintenance... off to check the PSB twitter.
EDIT: Twitter puts the last maintenance downtime 4 days ago.
October 2nd.
Originally posted by another user
The PlayStation Network is currently undergoing maintenance. Some users may not be able to connect.
Later That day
Originally posted by another user
...and the maintenance is complete. You should have no problems logging back in to the PSN. Enjoy your weekend!