Here's a link to a Christmas song I sung using the Auto-Tune feature in the app. Unfortunately, I'm not well-versed in many T-Pain songs. But, E_Diddy_84 on Twitter is a PRO at using the app!
Check out the video he made to enter in the Smule I Am T-Pain contest!
The popular iPhone app even made the Jimmy Kimmel Show:
And other artists got a chance to use I Am T-Pain. I love Akon's response. :)