Sony advises against using older PS3's for now.

Sony believes they have narrowed down the problem to the clock functionality. While the Slim models are unaffected by this Sony is advising that those of you who own older PS3′s do not use them for now.

We hope to resolve this problem within the next 24 hours. In the meantime, if you have a model other than the new slim PS3, we advise that you do not use your PS3 system, as doing so may result in errors in some functionality, such as recording obtained trophies, and not being able to restore certain data.

So far these are the reported errors:

The date of the PS3 system may be re-set to Jan 1, 2000.
When the user tries to sign in to the PlayStation Network, the following
message appears on the screen; “An error has occurred. You have been
signed out of PlayStation Network (8001050F)”.
When the user tries to launch a game, the following error message appears
on the screen and the trophy data may disappear; “Failed to install
trophies. Please exit your game.”
When the user tries to set the time and date of the system via the
Internet, the following message appears on the screen; “The current date
and time could not be obtained. (8001050F)”
Users are not able to play back certain rental video downloaded from the
PlayStation Store before the expiration date.

So much for having an error proof system Sony. I think this could be as bad if not worse than the Xbox 360′s Red Ring of Death. Those of you that are not aware what is happening please read this article which gives more information about the PlayStation Network being down.