The official Planetside2 twitter account reported this morning that hte beta will start soon and to look for "an approximation during E3" so we should know before the end of the week when (open?) beta will approximately start.
@chrono_2010 Beta will begin very soon. Look for an approximation during E3. [RadarX]
— PlanetSide 2 (@planetside2) June 6, 2012