Sitake leaves BYU after the season for the HC job at Oregon State. For one, the Poly pipeline would be well-suited for a West Coast team like OSU. On local Sports Radio this morning, they were saying that Ken Niumateulo (sp) is an attractive candidate that OSU is looking closely at. Sitake was OSU's DC prior to coming to BYU. Sitake has probably seen enough of the difficulties BYU faces (no conf, HC, few bruthas, etc) to know this is a sinking ship, at least for now.
As for who might be BYU's new HC, if my prediction is accurate, a crazy prediction there is Darrell Bevell, the Seahawks longtime OC...who most Seahawk fans don't care for. Bevell is an RM and a great guy. I could see him making the switch as he's supposedly wanted to be a HC for a few years, yet no NFL team wants him.