Just a quick note to let you know that firmware update 3.15, an optional update that was released in early December, is now a mandatory update. You can read about the contents of the update in the original post here.
In addition to the features that were communicated back in December, the update also improves system stability during use of some PlayStation 3 software. If you've already performed the update, there's no need to do anything. If you are using an older version of the firmware, you will be prompted to update when you start up your system and when you access any network features.