Download Autotalent:

Vocal harmonizer and autotune plugin

Autotalent by Oli Larkin is a great real-time pitch correction auto-tune VST plug-in. The Autotalent plugin ensures that only the specified notes are hit. Use this auto-tune VST plugin to make Cher-like vocal effects, or use it as a simple pitch shifting / pitch correction audio effect.
You might have to disable multiprocessor support in your vst host for it to work.