Namco Bandai will be conducting a closed beta for Dark Souls II starting on October 12th, but the registration process for this beta starts now. If you wanted to get into the beta, you can go to their page and apply. Namco Bandai also mentioned that they will be opening a second round of players on October 27th so there is plenty of opportunity to get into the beta. They are currently looking for players in North America, Europe and Australia.
Dark Souls II will be available in March 2014 for PC, Xbox 360 and PlayStation 3.