I finally finished a tutorial on how to add autotune to vocals using completely free software (LMMS, GSnap and AAS autotune).  I tried to make GSnap and AAS autotune sound as much like T-Pain as I could.  I’m mostly happy with how my vocals turned out but I think Commercial autotune likely works/sounds better.

This tutorial uses html5 audio tags instead of flash.  When I have time, I plan to convert most or all flash on my website to html5.