Their are alot of them.
Well although I dont know of all time, the current youngest coach is Pat Fitzgerald of Northwestern.
Paul "Bear" Bryant for Alabama.
Danny Ford guided Clemson University to its first and only national championship in 1981, and remains the youngest head coach in NCAA history to win a national title, accomplishing the feat at the age of 33.
Branch McCracken was the 31 year old coach of Indiana in 1940 when the Hoosiers won the NCAA championship by defeating Kansas, 60-42.
Coach Billy Joe, Central State University (Ohio)