Sony says some PSN services will return this week , and it appears Japan is already back up and functioning.
According to various sources and reports, there have been plenty of Twitter and Facebook entries that claim the Japanese Network has returned, although gamers in North America and Europe have no such luck just yet. Apparently, U.S. users can expect the PSN to be back up tomorrow, which just so happens to be the normal update day…sadly, without the Store, that won't mean much. We won't be able to access the Store for some time yet, although we should be able to play online with the resuming of services this week; and "this week" may mean "really soon." Also, just as a reminder, you will receive a mandatory firmware update that requires you to change your PSN password. You may also want to change some other data, if you're still leery about the system's stability.
At any rate, we'll keep a close eye on the PSN's status 'round these parts. Feel free to let us know the instant you see service return.