The latest PlayStation 3 firmware update (3.66) is now live and waiting to be downloaded.
It's a mandatory download so prepare to be put on hold for a while when you boot up your PS3.
It is only a minor update though, with "system stability during use of PS3 format software and network services" being listed as the improvements to be packaged on 3.66 by Sony yesterday. That means the download shouldn't take up too much of your time.
This is the second minor PlayStation 3 update of the month. Firmware 3.65 was optional and implemented more stability to the system.