rs-met releases Pitch Shifter, a free VST effect plugin for Windows. It shifts the pitch of an incoming audio signal. You can also mix the pitch shifted signal with the original signal via the dry/wet control, and that way basic detuning, octaving and harmonizing effects are also possible.
"This shifter is based on a delayline with two crossfaded read pointers. Such an architecture allows for feedback - and feedback gives the potential to rather drastic, weird special effects like monster-voices, flanger-like effects and more." Via