Be sure to check out yesterday's comic, uploaded just minutes before this one (so you probably missed it) due to scanner troubles. Until tomorrow: peace.
Autotune is a type of vocal processing that essentially "snaps" the singer into pitch. Its particularly noticeable when the singer does a pitch sweep, and you get individual pitch steps instead. T-pain used it on the "I'm on a Boat" sketch. Owl City uses it for all vocals.