UPDATE: (Sep 30) GameNet has announced that the 7 day early access program for those who purchased premium founder's packs will begin on October 5th, basic founder's packs on October 8th and with the full open beta to begin on October 12th. All iterations of the OBT will, at this time, take place on F2P servers. P2P server information will be updated at a later time.
GameNet has announced that the open beta for Black Desert Online will begin on October 12th. The team will be on hand this weekend during Russia's Igromir games festival where players can interact with both BDO and the publishing team. GameNet will reveal more details soon.
To celebrate the announcement, GameNet released a brand new trailer. Check it out as it's an interesting mix of live-action and cinematic quality filming.
See also the MMORPG.com forum thread.