Board Thread:Dark Souls II/@comment-5264386-20131018105419/@comment-5264386-20131018111130

Beta Invites (8th October, 2013)
Dark Souls II beta invites are being rolled out in North and South America, Europe and the UK at "Oct. 8 at 11:00 a.m. PDT". With more than 5,000 invitations being issued, it'll be a case of "first in, first served", with the redeemable code needed to download the client being disabled after the 5,000th invitee redeems their code.

Also, progress from the beta will not be transferrable to the retail version of Dark Souls II.

Source
http://www.examiner.com/article/dark-souls-2-north-american-beta-selection-testing-rounds-and-more-revealed