Playstation Blog has gone and made the dates official for the Resistance 3 Multiplayer Beta and the Assassins Creed: Revelations Multiplayer Beta. Resistance 3 Multiplayer Beta will come with the August 23rd 2011 Playstation Network Update and Assassins Creed: Revelations will come with the September 9th 2011 Update. As always these are for Playstation Plus members so if you were waiting to order your Plus membership, now would be the time.
Source Link: Playstation Blog