Per Twitter, possibly 10 BCS schools could have HC openings. I'm not including Ohio State because I'm guessing Urban will take it when it's all said and done.
Texas A&M
Tennessee
Penn State
UCLA
Illinois
Arizona State
Washington State
Kansas
Ole Miss
North Carolina
As for possible non-BCS openings:
Akron
Florida Atlantic
Memphis
Fresno State
UAB
Colorado State
A couple good sites to follow coaching carousel news:
Football Rumor Mill
Football Scoop