Georgia State University
Georgia State University: Hyper Physics: Pitch = Frequency of Sound
Pitch is the ear's response to frequency, and here you can get a better understanding of pitch, its measurement and the perception of pitch.
Other
Transverse and Longitudinal Wave Propagation in an Elastic Medium
Extensive information about how waves behave in an elastic medium. Covers different types of waves, their characteristics and behavior, the anatomy of the ear, the speed of sound in different media, the parts of a wave, and wave phenomena.
Physics Classroom
The Physics Classroom: Sound Properties and Their Perception
The concept of pitch and frequency is covered in this tutorial. Learn what frequency and pitch are, the difference between infra sound and ultrasonic frequencies, and how pitch is related to the frequency of a sound.