'If your bike has simple platform pedals or pedals with toe clips and straps, all you need to know is that the widest part of the foot should be centered over the pedal axle. If you use clipless pedals, which firmly attach to cleats bolted to your cycling shoes, you must also make sure that your cleats are adjusted so that your foot placement on the pedals is the same as your natural foot position while standing...' More / Another view on bike fitting / APTA guide
