|Soon-to-be-former-Gov. John A. Kitzhaber, M.D.|
(source: The Statesman Journal)
His public statement can be read at The Statesman Journal.
In accordance with Article V, Section 8a of the Oregon Constitution, Secretary of State Kate Brown will take over as Governor until the next biennial general election (November, 2016), and will appoint someone to serve out the remainder of her term (which ends at the same time). At that point, both seats are up for grabs; Mrs. Brown gets to decide whether to run to keep the Governor's seat for the remaining two years of the term, or step down and run for her normal Secretary of State re-election.
It's always a sad day when a scandal-wracked executive needs to resign, but we can't say we didn't see this coming.