The new Firmware update for the PS3 was scheduled to be live yesterday, but Sony has confirmed that the release is bring delayed by a week. Firmware 3.40 will now be released on June 29th 2010, the same day the PlayStation Plus subscription service is released.
The new firmware update will be required by anyone who signs up to the service to make use of automatic updates, and will also be required to access the PlayStation Store and online gameplay. The delay is likely to be caused by the threat of a new exploit found in the system.