In an interview on the official SWTOR website, Karpyshyn gives us a tease as to how this novel will relate to the new MMORPG.
I think the novel will give them a much better understanding of the Sith Emperor and the Empire, for one thing. The Old Republic Sith Empire is very different from what people know from the movies, or even from the Great Hyperspace War comics that focus on characters like Naga Sadow and Ludo Kressh.Although he does not mention an exact date for the book's release, we do know that it will come later this year. This reporter hopes that it is before the release of SWTOR.
The novel will also give them some very direct background and detailed information that ties in directly with key Flashpoints in the game. I can't say too much, of course, but like any great prequel the books will give you the details of what came before to add an extra layer of depth to the experiences in the game.