For pitch shifting the signal is ran through the phase vocoder as it does for the time scale operation (with a time stretch factor that of the pitch shift factor). This time stretched signal is then resampled as though its original sample rate was Fs*shiftFactor and the new sample rate as Fs (the original sample rate). When the sound is played back you hear a sound at the original sample rate that is pitch scaled by the factor supplied.

Original Signal

Pitch shifted by a factor of 2

M Files:
Example
pitchShift.m

Wave File Examples:
Wave File 2 - Shift one octive up
Wave FIle 2 - Shift one octave down
Wave File 2 - .5X stretch