During their financial announcements today, Take Two revealed that Bioshock 2 will be developed by the newly formed 2k Marin.  2k Marin has been founded by a few employees from 2k Boston, which developed the original Bioshock.

"We’re focused on continuing to bring new brands and cutting-edge gameplay to market with the creation of the 2K Marin studio. 2K Marin will build upon our success in creating and leveraging triple-A franchises," Christoph Hartmann, president of 2K, commented at the time.

You can expect to see Bioshock 2 on in your Xbox 360 at some point slightly before Christmas 2009.