Facebook just released a post stating that they will be gradually releasing the new design to all over the next week. This announcement comes late, as I had originally announced the new design to go out to all on August 27.
The new design has been both loved and hated by many, but has shown significant improvement since launch. It will be very interesting to see the response as all 100+ million of their users embrace the new design. Most of all, this should come as welcome news to developers, as they no longer have to support more than one design in their applications. All developers should now be able to start planning fully for the new design.
In addition to this news, it will also mean that permanent session keys will be dissolved (one week after the rollout), meaning it will be harder for external websites to log users into Facebook to authenticate and communicate with the API. It will be interesting to see, as they roll this out, if they also introduce Facebook Connect live to all next week to resolve this problem fully.