According to Corkran's article, sources close to the organization as well as Hue Jackson say the hiring will be made official very soon, even if Hue Jackson hasn't officially interviewed for the position.
In a corresponding blog post, Jerry McDonald (of the Oakland Tribune as well) expects the announcement to come after all NFL games are played. This would translate to an announcement coming late Sunday afternoon (on the West Coast) at the very earliest although, realistically, Monday or Tuesday would be a safer bet.
This is huge news as it is important to get the coaching ducks in a row so the Raiders can get a headstart on the NFL draft. Perhaps more importantly, it will settle the staff so they can begin to focus on "re-recruiting" the multitude of pending free agents this offseason.