Once more Sony has decided to bring down the PlayStation Network for Maintenance. It seems to me that they bring it down quite often compared to other Game Online Networks.
The maintenance shall commence on Monday, December 3, and will be down from 8am PT/11am ET to 4pm PT/7pm ET.
Luckily and as always before, if you use PSN right before the maintenance you should still be able to play online Monday. But PlayStation Home, the PlayStation Store and account management won't function until the maintenance is complete
Source: PlayStation Network