Star Wars: The Old Republic players will have to adjust to a new system of leveling and advancing when the Discipline system goes live with the expansion. But you can start preparing yourself, at least. A prototype Discipline Calculator is now available on Dulfy.net courtesy of swtor_miner; it utilizes data presented during livestreams as a starting point for building a reasonable picture of the trees.
As of this writing, the only advanced class available to play with is the Sith Sorcerer, but clicking around on the calculator should at least clarify the structure if not the details for all of the various classes. The calculator will likely be expanded as more data become available; until then, you can play around with what's provided.