Here you go...from 1935 to 2006

The top 3 conferences

BIG 10= 15 winners
BIG 12= 12 winners
PAC10= 10 winners

Notre Dame, USC, and Ohio State are the schools with the most wins at 7 apiece.

I would guess big-10.

[edit] Winners by school
School Winners
Notre Dame 7
Ohio State 7
USC 7
Oklahoma 4
Army 3
Michigan 3
Nebraska 3
Auburn 2
Florida 2
Florida State 2
Georgia 2
Miami 2
Navy 2
Texas 2
Wisconsin 2
Yale 2
BYU 1
Boston College 1
Colorado 1
Chicago 1
Houston 1
Iowa 1
LSU 1
Minnesota 1
Oklahoma State 1
Oregon State 1
Penn State 1
Pittsburgh 1
Princeton 1
South Carolina 1
SMU 1
Stanford 1
Syracuse 1
Texas A&M 1
TCU 1
UCLA 1

the Big11Ten has 16... Chicago was a member of the conference many moons ago.