Sony have revised their maintenance plans for today. The PSN will now be down for longer, from earlier in the day. Yay.
Originally, the scheduled maintenance was to last from 16:00 GMT on Monday 4 March 2013, to 03:00 GMT on Tuesday 5 March 2013.
However, it appears that now the timings have changed:
Updated timing: PSN maintenance tomorrow, 3/4 from 5am - 9pm Pacific Time. Online play still accessible if you've logged in recently
— PlayStation (@PlayStation) March 4, 2013
In Brit time, that's now 13:00 GMT on March 4th, to 05:00 GMT on March 5th. As per usual, users will be unable to access the PlayStation Store, Account Management, Account Registration, or play online. Trophies will still be working, however, and will update on users' profiles once the PSN is operational again.
Sixteen hours. Sixteen! What the hell are you doing Sony? It had better be awesome.