Quote (dysgenics @ 30 Aug 2010 14:28)
you need to use a VST (use this) or DirectX (not this) or RTAS (pro-tools only) plugin. Or alternatively you can use a vocoder rack unit to get a similar sound.
If you already have an autotune plugin such as Antares, Melodyne or V-vocals you just need to add it as an insert to the track of choice. In sonar (the sequencing software I use) it would be under fx -> audio fx -> vst plugins. But on cubase and many others I have tried it will be under "inserts".
Insert or "Use as -> fx" or simply "Add fx".
Reaper uses the "Add fx" form.