Currently, any and all Fat PS3 owners will be unable to log onto the PSN due to an unexpected error. This seems to follow Sony's revamp of their Playstation website.

No online play is one thing. Another big issue seems to be PS3 games that have Dynamic Trophy support (such as Bioshock 2, Heavy Rain, Fallout 3). Basically, when you see a PS3 game that says 'Installing Trophies' while its loading up to the main screen, that's your Dynamic Trophy support.

And Date/Times are getting set back to Dec 31st, 1999. Y2K is becoming the Y2K10?

I know Sony will have this fixed up ASAP. I disabled my Internet Connection setting on my PS3, but I have yet to stick Heavy Rain in. Thanks, Sony. Now I have to wait longer to enjoy this game...

Update: Due to a programming glitch in the date/time settings in the PS3 (basically, it calculated that 4 years later, we were supposed to have a Feb 29th according to the calculations done for date and time settings) that conflicted with what was logged on the PSN, this seems to be the primary reason why every system failed at the same time. Sony expects a fix will be up and running within the next 24 hours. And they advise that anyone not play their PS3. However...

-PS1 and PS2 games should be okay as they do not support trophies. But if you do write game saves with your games on the system, they may get corrupted with the fix goes through. The same goes for any PS3 games that do not support trophies.

In other words, you can play any of the above in your system. But as long as you don't save anything before the fix goes through, you should be fine.