I haven't seen anything official about Jurgens taking over the book completely. He hasn't mentioned anything on his twitter feed, and nothing official from DC yet. It may be a "one-off" where Jurgens is filling both duties that month while Giffen takes a break, or just a mistake in the solicits.
God, I hope so. I really can't see myself picking up a Superman title written by Jurgens solo, especially after reading the horror that was JLI #1.