In Sith teachings, nothing is more important than the individual: the glorious center of the universe, around which all other lives pale in importance. But the planetary home of the Lost Tribe of the Sith is not the center of the universe, but a backwater — and the tribe’s legendary founders were little more than slaves themselves!
When the Lost Tribe suddenly rediscovers its forgotten origins, frustration and anger threaten to finish the society once and for all. But the past holds more secrets still — knowledge that, in the right hands, could place the evil rulers of Kesh on a path toward a greater destiny in the stars...

Lost Tribe of the Sith: Secrets is due to be released as a free download (PDF) from StarWars.com on 5th March and from online retailers.

e-Book Novella by John Jackson Miller
Del Rey ( & )

Approximately 3,000 years before the Battle of Yavin:
When the Sith ship Omen crash-landed on Kesh two thousand years ago, the crew encountered native barbarism and superstition. Now a violent millennium has reduced the Lost Tribe of the Sith to a similar state. While Sith teachings are remembered, honored, and violently practiced, knowledge of the Lost Tribe's true origins has all but vanished...more
The seventh title in the Lost Tribe of the Sith series is available for free download (PDF) from Suvudu.com.

e-Book Novella by John Jackson Miller
Del Rey ( & )

Approximately 3,960 years before the Battle of Yavin:
Cast into slavery by the machinations of the Sith, Ori Kitai believes she’s found her way back into the Lost Tribe and perhaps a whole lot more. Ori’s discovery of a second starship gives her the opportunity to avenge the humiliations heaped on her family by the decrepit Grand Lord. Indeed, she could turn their entire society upside down, offering escape from their planetary prison....more
The sixth title in the Lost Tribe of the Sith series is available for free download from StarWars.com.

Sue Rostoni, LucasBooks' Executive Editor, has announced via StarWars.com Forums that all eight Lost Tribe of the Sith novellas will be collated into a paperback anthology due to be released in August 2012.

UPDATE (31st Jan.): Shelly Shapiro, Del Rey's Editor, has announced via their Facebook page that the anthology will "include a brand-new Lost Tribe story--a long one!" It is unclear where on the Timeline this extra story fits: prior to, during or after the eight scheduled Lost Tribe of the Sith stories.
(Source: via EUCantina.net)