You can follow updates on the situation on the PlayStation Blog and through their official Twitter account.

I have a 80GB PS3 from the Metal Gear Solid 4 bundle and my Critter Crunch game save had disappeared when I tried to play it yesterday. Anyone else care to share the condition of their Spiderman machine?

Update: Joystiq has broken the news that the bug has been fixed. PSN is back online and your trophies should have returned to you. If your trophies are still absent, Joystiq recommends:

If you lost any Trophy data over the past 24 hours, there may be a way to salvage it. Launch the game for which you’re trying to restore Trophies and it should automatically recreate a Trophy data set on your PS3′s memory, which you can then sync with the PSN server (just by opening up your Trophy list in the XMB). Our Heavy Rain Trophies had vanished, but this trick brought them back from the ether.