Sony has issued official firmware version ***** via PSN.
It is strongly recommended that you DO NOT update until it has been confirmed safe.
Details soon.
Quote:
A new PS3 system software update, v3.56, will be released soon. This is a minor update that adds a security patch.
UPDATE #1: As expected, the new firmware kills all homebrew. The update includes a new .self file with a new, previously unknown, key inside. This means all homebrew tools will have to be updated in order to restore functionality. More to come.