taken offline for maintenance at 11:05AM ET this morning and is due to be back up-and-running again by 8PM ET. Sony announced the unexpected downtime in a tweet after maintenance had begun.
You may be able to access your friends list and other services sporadically, but Sony isn't making any promises as to how long even limited functionality will be possible. Oh, and if you see a screen with the ominous warning that "the PlayStation Network has been suspended," it's just a confusing way of saying that the network is down for service -- it doesn't mean your account has been suspended. Phew.
We'll leave it to your imagination to fantasize about all of the exciting changes that actually aren't happening behind-the-scenes, like the roll out of cross-game voice chat. Go ahead and muse with your fellow commenters while we put on a fresh pot of coffee. Won't you stay awhile?